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12OntarioTrafficManual

Traffic Signals

July 2001

iOntario Traffic Manual - July, 2001

Book 12 - Traffic Signals

Foreword

The purpose of the Ontario Traffic Manual (OTM) is toprovide information and guidance for transportationpractitioners and to promote uniformity of treatmentin the design, application and operation of traffic controldevices and systems across Ontario. The objective issafe driving behaviour, achieved by a predictableroadway environment through the consistent ,appropriate application of traffic control devices. Furtherpurposes of the OTM are to provide a set of guidelinesconsistent with the intent of the Highway Traffic Actand to provide a basis for road authorities to generateor update their own guidelines and standards.

The OTM is made up of a number of Books, which arebeing generated over a period of time, and for which aprocess of continuous updating is planned. Throughthe updating process, it is proposed that the OTM willbecome more comprehensive and representative byincluding many traffic control devices and applicationsspecific to municipal use. Some of the Books of theOTM are new, while others incorporate updatedmaterial from the Ontario Manual of Uniform TrafficControl Devices (MUTCD) and the King’s HighwayGuide Signing Policy Manual (KHGSPM).

The Ontario Traffic Manual is directed to its primaryusers, traffic practitioners. The OTM incorporates currentbest practices in the Province of Ontario. Theinterpretations, recommendations and guidelines in theOntario Traffic Manual are intended to provide an

Ontario TrafficManual

understanding of traffic operations and they cover abroad range of traffic situations encountered in practice.They are based on many factors which may determinethe specific design and operational effectiveness oftraffic control systems. However, no manual can coverall contingencies or all cases encountered in the field.Therefore, field experience and knowledge ofapplication are essential in deciding what to do in theabsence of specific direction from the Manual itselfand in overriding any recommendations in this Manual.

The traffic practitioner’s fundamental responsibility isto exercise engineering judgement and experience ontechnical matters in the best interests of the publicand workers. Guidelines are provided in the OTM toassist in making those judgements, but they shouldnot be used as a substitute for judgement.

Design, application and operational guidelines andprocedures should be used with judicious care andproper consideration of the prevailing circumstances.In some designs, applications, or operational features,the traffic practitioner’s judgement is to meet or exceeda guideline while in others a guideline might not bemet for sound reasons, such as space availability, yetstill produce a design or operation which may bejudged to be safe. Every effort should be made tostay as close to the guidelines as possible in situationslike these, and to document reasons for departuresfrom them.

ii Ontario Traffic Manual - July, 2001


Custodial Office

Inquiries about amendments, suggestions or commentsregarding the Ontario Traffic Manual may be directedto:

Traffic OfficeMinistry of Transportation, Ontario301 St. Paul Street, 2nd FloorSt. Catharines, OntarioL2R 7R4Telephone: (905) 704-2960Fax: (905) 704-2888E-mail: [email protected]

Acknowledgements

The production of this Ontario Traffic Manual Book12(Traffic Signals) was made possible as a result of thegenerous contributions of several individuals andorganizations. It is important to recognize thecontributions of the following individuals:

Authors

Gene Smallwood, McCormick Rankin Corporation

Stephen Schijns, McCormick Rankin Corporation

Mario Tedesco, McCormick Rankin Corporation

Mick Oliviera, McCormick Rankin Corporation

Technical Advisory Committee Members

Sai Bagha, Ministry of Transportation, Ontario

Paul Batchelor, Town of Oakville and InternationalMunicipal Signal Association representative

Andrew Beal, Ministry of Transportation, Ontario

Jim Bell, Regional Municipality of Ottawa-Carleton andMunicipal Engineers Associationrepresentative

Bill Brown, County of Simcoe

Peter Crockett, Regional Municipality of Peel andOntario Traffic Conference representative

Roger De Gannes, Ministry of Transportation, Ontario

Kari Fellows, Toronto Transporation

Mike Flanigan, City of Mississauga

Ray Hortness, Regional Municipality of Sudbury

Norm Kelly, Ministry of Transportation, Ontario

Steve Schijns, McCormick Rankin Corporation

Gene Smallwood, McCormick Rankin Corporation

Hart Solomon, City of Hamilton

Mario Tedesco, McCormick Rankin Corporation

Bruce Zvaniga, Toronto Transportation

iiiOntario Traffic Manual - July, 2001


1. GENERAL INFORMATION ............................................................................................................................................. 11.1 Introduction ......................................................................................................................................................... 11.2 Sections of This Book .................................................................................................................................... 11.3 Use of This Book ............................................................................................................................................... 21.4 Classification ....................................................................................................................................................... 21.5 Functions of Traffic Control Signals ....................................................................................................... 31.6 Signal Indications ............................................................................................................................................. 3

General ..................................................................................................................................................................... 3Continuity Of Operation ..................................................................................................................................... 3Recommended Practice For Standardized Displays .................................................................................. 4

2. LEGAL REQUIREMENTS ................................................................................................................................................. 52.1 General ................................................................................................................................................................... 52.2 Approval of Signal Designs ......................................................................................................................... 5

HTA Statute 144 (31) - Approvals .................................................................................................................. 52.3 Regulation 626 ................................................................................................................................................... 7

HTA Regulation 626 Sub-section 1. (1) - Minimum Signal Head Requirements ........................... 7HTA Regulation 626 Sub-section 1. (2) - Vertical Order of Signal Indications .............................. 8HTA Regulation 626 Sub-section 1. (3) - Use of Circular Signal Indications .............................. 10HTA Regulation 626 Sub-section 1. (4) - Two Signal Heads Required .......................................... 10HTA Regulation 626 Sub-section 1. (4.1) - Intersection Pedestrian Signals .................................. 11HTA Regulation 626 Sub-section 1. (5) - Height of Signal Heads .................................................. 12HTA Regulation 626 Sub-section 1. (6) - Ramp Metering Signals .................................................. 13HTA Regulation 626 Sub-section 1. (7) - Don’t Walk Signals .......................................................... 13HTA Regulation 626 Sub-section 1. (8) - Walk Signals ...................................................................... 14HTA Regulation 626 Sub-section 1. (9) - Mounting of Pedestrian Signals ................................... 15HTA Regulation 626 Sub-section 1. (10) - Signals Not At Intersections ...................................... 16HTA Regulation 626 Sub-section 1. (11) - Amber Left Turn Arrows ............................................... 16

3. OPERATIONAL PRACTICE ......................................................................................................................................... 183.1 Introduction ...................................................................................................................................................... 18

General .................................................................................................................................................................. 18Standardization .................................................................................................................................................. 18Signal Operations Report ............................................................................................................................... 18

3.2 Controller Operation .................................................................................................................................... 193.3 Determination of Intersection Operation .......................................................................................... 20

Table of Contents

iv Ontario Traffic Manual - July, 2001


3.4 Selection of Mode of Control .................................................................................................................. 21General .................................................................................................................................................................. 21Pre-timed or Fixed Mode ................................................................................................................................. 21Actuated Mode ................................................................................................................................................... 22Semi-actuated Mode ........................................................................................................................................ 22Fully-actuated Mode ......................................................................................................................................... 23System Operation .............................................................................................................................................. 23

General ................................................................................................................................................. 23Coordination ...................................................................................................................................... 24

Modes for Isolated Operation ........................................................................................................................ 253.5 Phase Determination .................................................................................................................................. 25

General .................................................................................................................................................................. 26Standard Movements ........................................................................................................................................ 26

General ................................................................................................................................................. 26Traffic Movements for Type 170 Controllers ............................................................................ 26Traffic Movements for NEMA Type Controllers ....................................................................... 27

Interval Sequence .............................................................................................................................................. 27Phase Diagrams ................................................................................................................................................. 27Two Phase Operation ....................................................................................................................................... 28Three Phase Phase Operation ........................................................................................................................ 28Multiple Phase Operation ............................................................................................................................... 28Pedestrian Phases .............................................................................................................................................. 29

General ................................................................................................................................................. 29Exclusive Pedestrian Phases .......................................................................................................... 31Pedestrian Signal Operation .......................................................................................................... 31

Left Turn Phase Justification .......................................................................................................................... 31General ................................................................................................................................................. 32Approximation ................................................................................................................................... 32Methods of Analysis ........................................................................................................................ 32

Determination of the Type of Left Turn Phase ......................................................................................... 34General ................................................................................................................................................. 34Types of Left-Turn Phasing ............................................................................................................ 35

3.6 Timing ................................................................................................................................................................ 43General ................................................................................................................................................................ 43Minimum Interval Timing ............................................................................................................................... 43Calculation of Clearance Interval Timing .................................................................................................. 43

General ................................................................................................................................................. 43Amber and All-Red Clearance Intervals .................................................................................... 44Clearance for Left Turn Signals .................................................................................................... 44

Level of Service .................................................................................................................................................. 44General ................................................................................................................................................. 44LOS Based on Delay ........................................................................................................................ 46LOS Based on Probability of Clearing the Arrivals ................................................................ 46

vOntario Traffic Manual - July, 2001


LOS Based on Volume/Capacity (V/C) Ratio ......................................................................... 46Determination of Green Interval Timing .................................................................................................... 46

General ................................................................................................................................................. 46Ministry of Transportation Methodology .................................................................................. 46Canadian Capacity Guide Methodology ................................................................................... 47Highway Capacity Manual Methodology .................................................................................48Calculation of Green Extension Time ........................................................................................48

Determination of Delays On Actuation ......................................................................................................48Calculation Of Pedestrian Timing ................................................................................................................48

General .................................................................................................................................................48Method A (TCSTCA23) ..................................................................................................................... 49Method B (CCG1) ............................................................................................................................. 49Method C (Metro Toronto17) .......................................................................................................... 50Pedestrian Actuation ........................................................................................................................ 50

Determination of Cycle Length ..................................................................................................................... 50Guidelines ............................................................................................................................................51Cycle Composition ............................................................................................................................51

3.7 Signal Spacing ................................................................................................................................................. 51Existing Intersection Analysis ........................................................................................................................ 52New Signalized Intersections ......................................................................................................................... 52

3.8 Flashing Operation ........................................................................................................................................ 53Advanced Green Flashing Operation ......................................................................................................... 53Standardized Flashing Operation ................................................................................................................. 53

3.9 Preemption ........................................................................................................................................................ 54General ................................................................................................................................................................ 54Preemption For Railway Crossings .............................................................................................................. 54Preemption For Emergency Vehicles .......................................................................................................... 55

3.10 Operation Of Miscellaneous Signals .................................................................................................... 56Pedestrian Signals ............................................................................................................................................. 56Transit Priority Signals ...................................................................................................................................... 56Moveable Span Bridge Traffic Control Signals ......................................................................................... 56Lane Direction Signals ..................................................................................................................................... 57Portable Lane Control Signal Systems ........................................................................................................ 57Audible Indications ........................................................................................................................................... 57Tunnel Signals .................................................................................................................................................... 58Ramp Metering Signals ................................................................................................................................... 58

3.11 Flashing Beacon Signals ............................................................................................................................ 58General ................................................................................................................................................................ 58Hazard Identification Beacons ....................................................................................................................... 59Beacons in Advance of A Signalized Intersection .................................................................................. 59Intersection Control Beacons ......................................................................................................................... 59

General ................................................................................................................................................. 591-Way or 2-Way Overhead Red Flashing Beacons ................................................................ 59

vi Ontario Traffic Manual - July, 2001


3-Way and 4-Way Overhead Red Flashing Beacons ............................................................ 593-Way and 4-Way Overhead Red/Amber Flashing Beacons ............................................. 60Red Beacon For Stop Sign Reinforcement ............................................................................... 60

Warning Beacons at Signalized Intersections ........................................................................................... 60Continuous Advance Warning Beacons for Traffic Signals ............................................... 60Active Advance Warning Beacons for Traffic Signals ......................................................... 60

3.12 Systems .............................................................................................................................................................. 61Need For A System........................................................................................................................................... 61Types Of Systems .............................................................................................................................................. 62

General ................................................................................................................................................. 62Arterial Interconnected System .................................................................................................... 62Grid Interconnected System .......................................................................................................... 63Small Central System ...................................................................................................................... 63Large Central System ....................................................................................................................... 63Traffic Adaptive System ............................................................................................................... 63

4. PLANNING AND JUSTIFICATION .......................................................................................................................... 644.1 General ................................................................................................................................................................ 64

Purpose ................................................................................................................................................................ 64Background/Context ......................................................................................................................................... 64Current Update ................................................................................................................................................... 64

4.2 Information Requirements ........................................................................................................................ 66Basic Input Data ................................................................................................................................................ 66Supplementary Input Data ............................................................................................................................. 66

Vehicle Delay ...................................................................................................................................... 66Gaps (Unsignalized Intersections Only) ..................................................................................... 66Site Conditions .................................................................................................................................. 66Future Demand .................................................................................................................................. 66

4.3 Principles of Justification .......................................................................................................................... 67General ................................................................................................................................................................ 67Guidelines and Exceptions ............................................................................................................................. 67Definitions ............................................................................................................................................................ 67

4.4 Justification 1 - Minimum Vehicle Volume ...................................................................................... 69Purpose ................................................................................................................................................................ 69Standard ............................................................................................................................................................... 69Guidelines ............................................................................................................................................................ 70

4.5 Justification 2 - Delay To Cross Traffic .............................................................................................. 70Purpose ................................................................................................................................................................ 70Standard ............................................................................................................................................................... 70Guidelines ............................................................................................................................................................ 71

4.6 Justification 3 - Collision Experience .................................................................................................. 72Purpose ................................................................................................................................................................ 72

viiOntario Traffic Manual - July, 2001


Standard ............................................................................................................................................................... 72Guidelines ............................................................................................................................................................ 72

4.7 Justification 4 - Combination Justification ...................................................................................... 73Purpose ................................................................................................................................................................ 73Standard ............................................................................................................................................................... 74Guidelines ............................................................................................................................................................ 74

4.8 Justification 5 - Pedestrian Volume and Delay ............................................................................... 74Purpose ................................................................................................................................................................ 74Standard ............................................................................................................................................................... 75Guidelines ............................................................................................................................................................ 76

4.9 Signal Justifications For Future Conditions ..................................................................................... 784.10 Signal Installation Prioritization .............................................................................................................. 794.11 Summary of Signal Justification ...........................................................................................................804.12 Justification for Temporary Traffic Control Signals .................................................................... 814.13 Justification for Bicycle Signals ............................................................................................................. 814.14 Removal of Existing Signals ..................................................................................................................... 81

5. DESIGN PRACTICE ........................................................................................................................................................ 825.1 General ................................................................................................................................................................ 82

Use Of This Section .......................................................................................................................................... 825.2 Practical Requirements ............................................................................................................................... 825.3 Safety Considerations ................................................................................................................................. 825.4 Future Considerations ................................................................................................................................. 835.5 Signal Visibility ................................................................................................................................................ 83

General ................................................................................................................................................................ 83Signal Head Locations ..................................................................................................................................... 84Viewing Angles .................................................................................................................................................. 85Lateral Signal Head Locations ....................................................................................................................... 85Median Mounted Signal Heads ..................................................................................................................... 86Visibility Distance .............................................................................................................................................. 86Backboards .......................................................................................................................................................... 86Mounting Height ................................................................................................................................................ 87Obstruction By Other Signal Heads ............................................................................................................ 87Auxiliary Signal Heads And Beacons ......................................................................................................... 88

General ................................................................................................................................................. 88Auxiliary Heads at Bridge Obstructions .................................................................................... 88Auxiliary Heads at Geometric Curve Obstructions ................................................................ 88Obstructions Due to Large Vehicles ........................................................................................... 89

Optically Programmable Signal Heads .......................................................................................................905.6 Pole And Signal Head Locations ............................................................................................................90

Primary Signal Head Locations .....................................................................................................................90General .................................................................................................................................................90

viii Ontario Traffic Manual - July, 2001


With Median Islands ........................................................................................................................ 92Without Median Islands ................................................................................................................. 92

Secondary Signal Head And Pole Locations ............................................................................................ 92General ................................................................................................................................................. 92With Median Islands ........................................................................................................................ 92Without Median Islands ................................................................................................................. 92

5.7 Pedestrian Signal Heads ............................................................................................................................. 93Pedestrian Indications ...................................................................................................................................... 93Guidelines For Pedestrian Signal Head Installation ................................................................................ 93Guidelines For Pedestrian Pushbuttons ..................................................................................................... 94Mounting Height And Location .................................................................................................................... 94

5.8 Miscellaneous Traffic Control Signals ................................................................................................ 94Intersection Pedestrian Signals ...................................................................................................................... 94Mid-block Pedestrian Signals ......................................................................................................................... 95Lane Direction Signals ..................................................................................................................................... 95Ramp Metering Signals ................................................................................................................................... 96Signals Near Railway Crossings .................................................................................................................... 96Transit Priority Signals ...................................................................................................................................... 96Moveable Span Bridge Signals ..................................................................................................................... 97Portable Lane Control Signals ....................................................................................................................... 97Signals With Audible Indications ................................................................................................................. 97Tunnel Signals .................................................................................................................................................... 97Bicycle Control Signals .................................................................................................................................... 97

5.9 Detection ............................................................................................................................................................ 98General ................................................................................................................................................................ 98Presence Loop Detectors ................................................................................................................................. 98Long Distance Loop Detectors ...................................................................................................................... 99

5.10 Layout Design ............................................................................................................................................... 100General ............................................................................................................................................................. 100Crosswalks And Sidewalks ......................................................................................................................... 100

General .............................................................................................................................................. 100Design of Crosswalks and Sidewalks ...................................................................................... 101

5.11 Utilities ............................................................................................................................................................. 104General ............................................................................................................................................................. 104Guidelines ......................................................................................................................................................... 104

5.12 Layout Practice ............................................................................................................................................. 105General ............................................................................................................................................................. 105Guidelines By Example ................................................................................................................................. 105“T” Intersection Approach ............................................................................................................................ 106Approach Without Median Island (Normal Or Advanced Green) ................................................... 106Approach Without Median Island (Fully Protected Left Turns) ........................................................ 107Approach With Median Island (Normal, Advanced Green Or SimultaneousProtected /Permissive Lefts) .........................................................................................................................107

ixOntario Traffic Manual - July, 2001


Approach With Median Island (Fully Protected Left Turns) .............................................................. 108Approach With Wide Median (Fully Protected Left Turns) ............................................................... 109Approach With Double Left Lane (Fully Protected Left Turns) ........................................................ 109Ramp Terminal .................................................................................................................................................. 111Short Offset Intersection ................................................................................................................................ 111Long Offset Intersection ................................................................................................................................ 112Layout Of Pedestrian Heads And Poles .................................................................................................... 114

General ............................................................................................................................................... 114Poles With Pushbuttons ............................................................................................................... 114Poles With Pedestrian Heads ...................................................................................................... 115

5.13 Controller Locations ................................................................................................................................... 115Coordination ..................................................................................................................................................... 115Physical Requirements ................................................................................................................................... 116

5.14 Design Example ............................................................................................................................................ 117General .............................................................................................................................................................. 117Preparation Of Base Plan .............................................................................................................................. 117Layout Of Crosswalks And Sidewalks ...................................................................................................... 118Pole Locations .................................................................................................................................................. 118Pre-set Head and Pole Locations ................................................................................................................ 119Layout Of Primary And Secondary Heads .............................................................................................. 119Layout Of Pedestrian Facilities .................................................................................................................... 119Checking Layout .............................................................................................................................................. 119Controller And Power Supply Locations ..................................................................................................120Detector Layout ................................................................................................................................................ 121Duct And Wiring Systems ............................................................................................................................122Coordination Of Lighting Design ...............................................................................................................122

6. MISCELLANEOUS ........................................................................................................................................................ 1276.1 General .............................................................................................................................................................. 1276.2 Standard Equipment .................................................................................................................................. 1276.3 Other Considerations ................................................................................................................................. 127

Structural Considerations ............................................................................................................................. 127Electrical Considerations ............................................................................................................................... 127Aesthetic Considerations .............................................................................................................................. 128

6.4 Lamps, Lenses & Visors ........................................................................................................................... 129Lamps .............................................................................................................................................................. 129Lenses .............................................................................................................................................................. 129Visors .............................................................................................................................................................. 129

x Ontario Traffic Manual - July, 2001


TABLES

Table 1 - Relative Vertical Positions of Signal Indications ........................................................................................................ 8Table 2 - Controller Operations Types for Isolated Operation .............................................................................................. 26Table 3 - Capacity Factor for Opposing Lanes ......................................................................................................................... 32Table 4 - Minimum Timing Intervals ............................................................................................................................................ 43Table 5 - Amber Clearance Interval Times ................................................................................................................................. 45

Table 6 - All-Red Clearance Interval Times ................................................................................................................................ 45Table 7 - LOS Based on Delay ........................................................................................................................................................ 46Table 8 - LOS Based on Clearing Arrivals ................................................................................................................................... 46Table 9 - LOS Based on Volume/Capacity ................................................................................................................................. 46Table 10 - Information to be Collected ....................................................................................................................................... 65

Table 11 - Basic Input Data .............................................................................................................................................................. 67Table 12 - Justification 1 - Minimum Vehicle Volume for Restricted Flow (Urban) Conditions .............................. 70Table 13 - Justification 1 - Minimum Vehicle Volume for Free Flow (Rural) Conditions ........................................... 71Table 14 - Justification 2 - Delay To Cross Traffic for Restricted Flow (Urban) Conditions ..................................... 72Table 15 - Justification 2 - Delay To Cross Traffic For Free Flow (Rural) Conditions .................................................. 73

Table 16 - Justification 3 - Collision Experience ..................................................................................................................... 74Table 17 - Justification 4 - Combination Justification ........................................................................................................... 74Table 18 - Pedestrian Volume Data Summary .......................................................................................................................... 75Table 19 - Pedestrian Delay Data Summary ............................................................................................................................... 75Table 20 - Pedestrian Volume Justification 5A ........................................................................................................................ 76

Table 21 - Pedestrian Delay Justification 5B ............................................................................................................................. 76Table 22 - Summary of Signal Justification ..............................................................................................................................80Table 23 - Signal Installation Prioritization .................................................................................................................................80Table 24 - Signal Visibility Distances ........................................................................................................................................... 85Table 25 - Typical Use of Signal Heads and Backboards ...................................................................................................... 86Table 26 - Distances from Stop Line for Long Distance Loops ........................................................................................ 100Table 27 - Commonly Used Lamps for Traffic Signals ........................................................................................................ 129

xiOntario Traffic Manual - July, 2001


FIGURES

Figure 1 - Traffic Control Signal Heads ........................................................................................................................................... 9Figure 2 - Type 170 Fazes ............................................................................................................................................................... 27Figure 3 - NEMA Movements ......................................................................................................................................................... 27Figure 4- Multi-Phase Diagrams With Protected Operation on Both Roads ................................................................... 29Figure 5 - 2-Phase Diagram ............................................................................................................................................................ 30Figure 6 - Three Phase Diagrams .................................................................................................................................................. 30Figure 7 - Protected/Permissive Intervals .................................................................................................................................... 35Figure 8 - Protected/Permissive Simultaneous Left Turn Operation .................................................................................. 36Figure 9 - Fully Protected Left Turn Operation .......................................................................................................................... 39Figure 10 - Extended Green Intervals ........................................................................................................................................... 40Figure 11 - Separate (Exclusive) Phasing ..................................................................................................................................... 41Figure 12 - Pedestrian Justification Based on Pedestrian Volumes .................................................................................... 78Figure 13 - Pedestrian Justification Based on Pedestrian Delay .......................................................................................... 79Figure 14 - Cones of Vision for Signal Visibility ...................................................................................................................... 85Figure 15 - Secondary Head Blocking Visibility ....................................................................................................................... 87Figure 16 - Auxiliary Heads at Underpass .................................................................................................................................. 87Figure 17 - Auxiliary Heads at Intersection on Curve ............................................................................................................. 87Figure 18 - Use of Continuous Flasher ........................................................................................................................................ 88Figure 19 - Use of Active Flasher & Sign .................................................................................................................................... 89Figure 20 - Optically Programmable Heads, Example in Wide Median ........................................................................... 89Figure 21 - Optically Programmable Heads, Example on Parallel Roads ......................................................................... 89Figure 22 - Primary and Secondary Heads Without Islands ................................................................................................90Figure 23 - Primary and Secondary Head Locations .............................................................................................................. 91Figure 24 - Intersection Pedestrian Signals ................................................................................................................................ 94Figure 25 - Presence Loops ............................................................................................................................................................. 99Figure 26 - Extension Loops ........................................................................................................................................................... 99Figure 27 - Crosswalk and Sidewalk Locations ...................................................................................................................... 101Figure 28 - Crosswalk Design....................................................................................................................................................... 101Figure 29 - Use of Right Turn Island ......................................................................................................................................... 103Figure 30 - “T” Intersection Approach ...................................................................................................................................... 106Figure 31 - Layout at Approach Without Median Island ...................................................................................................... 107Figure 32 - Approach With Fully Protected Left Turn Heads and Without Median Island ...................................... 108Figure 33 - Normal or Protected/ Permissive Layout ........................................................................................................... 109Figure 34 - Fully Protected Left Turn Approach .................................................................................................................... 109Figure 35 - Fully Protected Left Turn At Wide Median Approach .................................................................................... 110Figure 36 - Fully Protected Dual LTL Approach ....................................................................................................................... 111Figure 37 - Ramp Terminal Intersection Approach ................................................................................................................ 112Figure 38 - Short Offset Intersection ......................................................................................................................................... 113Figure 39 - Long Offset Intersection .......................................................................................................................................... 113Figure 40 - Layout of Poles With Pushbuttons ....................................................................................................................... 114Figure 41 - Base Plan Features ..................................................................................................................................................... 118

xii Ontario Traffic Manual - July, 2001


Figure 42 - Crosswalk and Sidewalk Modifications .............................................................................................................. 119Figure 43 - Pole Areas Restricted by Utilities ..........................................................................................................................120Figure 44 - Pre-set Signal Locations ........................................................................................................................................... 121Figure 45 - Primary Head and Pole Layout .............................................................................................................................. 122Figure 46 - Secondary Pole and Head Layout ......................................................................................................................... 123Figure 47 - Layout of Pedestrian Facilities ................................................................................................................................ 124Figure 48 - Checking Signal Head Visibility and Layout ..................................................................................................... 124Figure 49 - Controller and Power Supply Location ............................................................................................................... 125Figure 50 - Detector Loop Layout ............................................................................................................................................... 125Figure 51 - Underground Duct System Layout ........................................................................................................................ 126Figure 52 - Partial Lighting ............................................................................................................................................................ 126

APPENDICES

APPENDIX A - GLOSSARY ...................................................................................................................................................... 131

APPENDIX B - REFERENCES ..................................................................................................................................................141

APPENDIX C - SIGNAL DESIGN CHECKLIST ............................................................................................................... 145

APPENDIX D - LEGEND ............................................................................................................................................................ 149

1Ontario Traffic Manual - July, 2001


1. General Information

1.1 Introduction

Book 12 of the Ontario Traffic Manual (OTM) replacesthe Manual of Uniform Traffic Control Devices(MUTCD), Chapter on Traffic Signals.

This is a user manual intended to provide someelementary instruction to beginners and to provide areference to experienced persons for the design andoperation of traffic signals. The intent is to provide arecommended best practice guide. This is not to saythat the recommended methods are the only methodsor are necessarily the best methods for the specificset of traffic control signals under consideration asmany factors are involved.

Users should recognize that the planning, design,application and operation of traffic control signals iscomplex; that all required information cannot be givenin a manual; and that extensive knowledge andexperience are required to be proficient in the field.

The material has been extensively revised from thatpreviously given in the MUTCD and has been updatedto reflect the following:

• the introduction of additional types of trafficsignals including Intersection Pedestrian Signals(IPS), Transit Priority Signals (TPS) and BicycleControl Signals (BCS);

• traffic signal needs and justificationsincorporating changes due to recentdevelopments;

• deletion of the requirement for Ministry approvalof municipal signal designs from the HighwayTraffic Act7 (HTA) and the consequent need toinclude more details on formation of designguidelines and procedures;

• the desire to emphasize the need forstandardization of signal displays across theprovince. This includes the need to provide asmuch information to Ontario road authorities as ispractical and the need to be compatible, wherepossible, with the Canadian national standard(TAC MUTCD12) and the U.S. standard11.

1.2 Sections of this book

• Section 1,General Information, gives generalinformation and basic signal concepts;

• Section 2, Legal Requirements, gives the legalrequirements pertaining to application of theHighway Traffic Act;

• Section 3, Operational Practice, givesguidelines and recommended practice foroperational features;

• Section 4, Planning and Justification, givesguidelines and recommended practice forjustifying the need for traffic signals;

• Section 5, Design Practice, gives guidelinesand recommended practice for design concepts,philosophy and details;

• Section 6, Miscellaneous Information, givesrecommended practices and guidelines formiscellaneous aspects.

This book refers to various publications produced bythe Ministry and other agencies such as the Instituteof Transportation Engineers (ITE), the InternationalMunicipal Signals Association (IMSA), theTransportation Association of Canada (TAC) and theOntario Traffic Conference (OTC). A reference sectionis provided in the book.

The manual uses acronyms and, of necessity, someindustry jargon. A Glossary is provided in the manual.



Where symbols appear for layout drawings, thesymbols legend may be found in Ontario ProvincialStandard Drawings 15 , Volume 4, Electrical Drawings,Division 2000. An abbreviated version of this legendmay be found in Appendix D.

1.3 Use of This Book

In this publication, the meaning of identifying termsare as follows:

”Legal Requirement(s)”, “Legally Required”,“Legal” and equivalent terms mean that therequirement is the law of Ontario as established underthe Highway Traffic Act 7 (HTA) and its Regulations.The requirement is typically described by the use of“shall” or “must”.

”Interpretation” means the interpretations andemphasis of the legal requirements . Theinterpretations are not necessarily precise wordinginterpretations of the HTA7 and Regulations. Manysmall items of application do not warrant a fulldescription under the legal documents and furtherinterpretation is required in the interests of safety,standardization throughout Ontario or otherrequirements. The interpretations are given in laylanguage and may include some jargon of the industry.The requirement is typically described by the use of“shall”.

“Recommended Practice” means the best mannerin which the legal requirements and interpretationsare applied using the typical procedures andequipment in use in Ontario. The recommendedpractices are not necessarily the only practicesavailable based on the interpretation of the legalrequirements or the selection of equipment ormethods of operation. The recommendation istypically described by the use of “should”.

”Guideline” means a suggested method of practicalapplication of the legal requirements andinterpretations using the typical procedures andequipment and methods of operation in use in Ontario.The guidelines are meant to provide guidance to thosein the traffic signal industry who may be unsure ofthe methods of application. A guideline has no legalconnotation and several alternate methods ofachieving the same result , consistent withstandardization, may be available to the user. Aguideline is typically described by the use of “may”.

1.4 Classification

Traffic signals include electrically operated trafficcontrol devices (except signs and pavement markings)which are recognized in the HTA 7 and by which trafficis warned or is directed to take some specific action.

Traffic signals may be classified as follows:

1. Traffic Control Signals are defined as those whichalternate vehicular and/or pedestrian right-of-wayand include the following:

• Full Intersection Traffic Control Signals;

• Intersection Pedestrian Signals (IPS);

• Midblock Pedestrian Signals;

• Bicycle Control Signals;

• Moveable Span Bridge Traffic Signals;

• Transit Priority Signals;

• Ramp Metering Signals;

• Portable Lane Control Signals;

• Train Approach Signals; and

• Lane Direction Signals.

2. Flashing Beacons:

• At Intersections; and

• Warning Of Other Special Hazards.



1.5 Functions Of Traffic ControlSignals

The function of a traffic control signal is to alternatethe right-of-way between conflicting streams ofvehicular traffic, or vehicular traffic and pedestrianscrossing a roadway, with maximum efficiency andsafety. Maximum efficiency implies the minimumdelay to traffic. Safety requires that the traffic controlsignals operate at the minimum hazard to vehiclesand pedestrians. Traffic control signals, as the nameimplies, are primarily control devices rather than safetydevices.

Traffic control signals can seldom be justified as safetymeasures alone since their installation does notnecessarily guarantee a reduction in collisionexperience. The practice of installing traffic controlsignals for reasons other than right-of-way control hasled to installations in some instances wherejustification is weak. Traffic waiting at a side roadstop sign may have lower overall delay without a signalthan would occur waiting for a signal change at anunjustified traffic control signal.

Unnecessary traffic control signals can lead toexcessive delay, increased use of fuel, increasedair pollution, increased noise, motoristfrustration, greater disobedience of the signalsand to the use of alternate routes in attemptingto avoid these types of signals. Unjustified trafficcontrol signals may alter the type of collisions and insome cases increase the collision frequency,particularly rear-end collisions, as opposed to right-angle collisions prevalent at intersections controlledby stop signs. Therefore, installation of trafficcontrol signals does not necessarily guarantee areduction in collision frequency although somesignals can be justified on a safety basis only.

Traffic control signals are to be used for the safe controland regulation of the movements of goods and people.Traffic control signals should not be used for trafficcalming schemes, for limiting traffic volumes onspecific routes, for speed control devices, for demandcontrol devices or for the discouragement of motoristsand pedestrians for use of a specific route.

Justification of traffic signals should be based onstudies and needs as outlined in Section 4.

1.6 Signal Indications

General

This Section describes the general usage of signalindications including some design and someoperational features.

The meaning and position of the various trafficcontrol signal indications described herein havebeen interpreted as standardized for use inOntario and should not be varied. The meaningof the indications may be clarified or qualified, whereappropriate, by a sign as identified in the OntarioTraffic Manual - Book 5 - Regulatory Signs.

Different operations and displays will depend on theneed to produce a given level of service at themaximum level of safety for traffic movements asdiscussed in Section 4.

Continuity Of Operation

Once a set of traffic control signals has been installed,it should always display some indication under normalconditions. It should never intentionally be turned offunless control is provided by a police officer or analternate method.



When the traffic signal is to be taken out ofservice for an extended period of time, the signalheads should be either removed or the lensescovered in such a manner that they are no longervisible to motorists and/or pedestrians. The absenceof any signal indication will help to warn motoriststhat the traffic signal is malfunctioning. When signalsare removed, some alternative form of control shallbe introduced for that period.

If due to a collision or reconstruction, some or all ofthe existing traffic signal heads have to be replacedor relocated, an interim installation of temporary signalheads should be considered. It is necessary tomaintain the proper and safe operation of theintersection. If the final repairs will take a considerableamount of time (e.g. longer than it is practical to keepa police constable on site) the interim installationshould be considered as being required. Thetemporary signal heads must conform to therequirements for traffic control signals.

Recommended Practice For StandardizedDisplays

In Ontario, standardization of the signal design for abasic two phase intersection has been achievedthrough the application and interpretation of theprinciples of the HTA7 and the previously publishedMUTCD10. The use of at least two vertically mountedsignal heads located on the far side of the intersectionfrom which traffic is approaching is a standard whichhas been used in Ontario for many years.

Traffic control signal lenses for vehicular traffic mustbe circular with a diameter of not less than 20 cm.At least the red indications of the primary signal headshall be 30 cm diameter. For roadways posted at 80km/h and over, it is recommended practice that bothprimary and secondary red indications be of 30 cmdiameter. All arrow indications shall be 30 cmdiameter.

The standardized traffic control signal indications shallbe shown by means of lenses not having visiblelettering nor insignia of any kind on their surface,excepting special signal lenses used for pedestriansignal heads, arrow indications and transit prioritysignals.

The lenses shall be illuminated and shall produce avisual display conforming to ITE Standard ST -01727

for chromaticity and luminance of the red, amber(“yellow” in ITE publications) and green displays andshall be clearly distinguishable under all normalconditions of visibility.

The standard indications used in Ontario are shownin Section 2, Figure 1.



2. Legal Requirements

2.1 General

Section 2 gives an interpretation of Subsection 144(31) and Regulation 626 of the Highway Traffic Act7

(HTA) together with recommended practice guidelinesand comments. The April, 1996 edition of Regulation626 is used.

2.2 Approval Of Signal Designs

HTA Statute 144 (31) - Approvals

1. General

A revision to The Highway Traffic Act (HTA), Sub-section 144 (31), was proclaimed into law in theOntario Legislature on March 3, 1997.


The following is the text of the revision:

(31) “Subject to subsection (31.1), no traffic controlsignal system or traffic control signal used inconjunction with a traffic control signalsystem shall be erected or installed except inaccordance with an approval obtained from aperson designated to give such approvals bythe municipality or other authority that hasjurisdiction over the highway or theintersection.

(31.1) No traffic control signal system or trafficcontrol signal used in conjunction with atraffic control signal system shall be erectedor installed on a highway designated as aconnecting link under subsection 21(1) of thePublic Transportation and Highway

Improvement Act except in accordance withan approval obtained from the Minister or anofficial of the Ministry authorized by theMinister to grant such approval.”

3. Interpretation

i Municipalities are responsible for designatinga person to approve traffic signal designs andinstallations on their own roadways;

ii The Ministry will still approve traffic signaldesigns and installations for connecting links;

iii For highways and ramp terminal intersectionsunder Ministry jurisdiction, the Ministry willcontinue to follow the practice of preparingform PHM-125 for each signal and these willbe reviewed and approved internally; and

iv For highways and ramp terminal intersectionsunder Ministry jurisdiction but where theMinistry has entered into maintenance andoperations agreements with municipalities,the particular municipality is responsible forpreparing form PHM-125 and submitting it tothe Ministry for approval.

4. Recommended Practice

i It is a recommended practice thatmunicipalities should follow a similarprocedure, within their own organizations ofpreparing, approving and updating trafficcontrol signal drawings to ensure that acompetent person reviews the design and inorder to assist in the protection of themunicipality should a traffic collision or othermishap occur. A continuing program of pro-active risk management including theapproval procedure is strongly recommended.

ii Where smaller municipalities are undertakingtraffic signal installations or modifications anddo not have a person experienced with thework, it is strongly suggested that the



municipalities engage qualified persons whocan design, and/or certify the design, prior toapproval by the designated persons of themunicipalities. These persons do not have tobe an internal staff member.

iii As a minimum, it is a recommended practicethat the traffic control signal plans should beproduced to a scale of 1:200, 1:250 or1:500. The plans should show theintersection details on all approaches for thedistance from the intersection which directlyaffects the signal operation (usually not lessthan 30 m) and should indicate, to scale, thefollowing (minimum) details:

• edge of roadway (edge of pavement or curband gutter), sidewalks, islands;

• legal and lane designation signs;

• property access (driveways, curb cuts,ramps);

• utility poles if signal attachments arerequired;

• the exact location, orientation and type oftraffic signal heads and pedestrian heads andtheir mounting height;

• the exact location of pedestrian signal headsand pushbuttons;

• geometrics as per Appendix C;

• pavement markings (centreline, lane lines,crosswalks, stop lines, turn arrows;

• blank-out signs and active or continuousflashing advance warning signs or othertypes of equipment operated by the signalcontroller; and

• detection devices and their location.

iv As a guideline, the following items may alsobe added to the plan at the option of theroad authority:

• location of traffic signal controller cabinet;

• electrical details such as underground ducts,electrical chambers and controller and powersupply locations;

• property lines, street lines, building outlines,parking meters and parking control;

• bus bays and bus stops;

• lane dimensions; and

• information/guidance signs.

v It is recommended practice that if signalheads are relocated or, if additional signalheads are installed, then re-approval of theentire installation is required by thedesignated approval person.

vi It is recommended practice that approvalplans should be prepared for both temporaryand permanent signals.



2.3 Regulation 626

HTA Regulation 626 Sub-section 1. (1) -Minimum Signal HeadRequirements


Sub-section 1.(1) states: “Every traffic control signalshall consist of one circular amber and one circularred indication in combination with,

(a) a circular green indication;

(b) a circular green indication and one or moregreen arrow indications;

(c) a circular green indication, one or moregreen arrow indications and one or moreamber arrow indications; or

(d) one or more green arrow indications.”

2. Interpretation

i Every traffic control signal must have amandatory circular red and circular amberindication;

ii Every traffic control signal head must have amandatory green indication.

iii The green indication may be composed of asingle circular green or a maximum of threegreen arrows, indicating only right, left andthrough traffic movements, or

iv Where a circular green indication is used(indicating that all traffic movements areallowed; a “permissive” display), only oneadditional green arrow indication may beused in the same signal head, indicating thateither left or right turns, specifically in onedirection only, are ”protected” frominterference from a conflicting trafficmovement;

v Where the green indication consists of eitherleft, right or through arrows or any propercombination thereof, with a circular green (forexample, with type 10 or 10A heads as perFigure 1), then the arrows indicate singleprotected movements which are active at thesame time as the circular green (and notindependently active), and one circular amberindication only shall be used. This type ofoperation may occur for instance at a “T”intersection facing the side road.


i For reasons of simplicity and physicalconstraints and to increase theireffectiveness, it is a recommended practicethat no more than five lens indicationsshould be combined in one signal head;

ii Every green indication (circular or arrow)must have an amber (circular or arrow)indication to indicate that the green intervalhas ended;

iii Where both a circular green and a left greenarrow indication are used to allow protected/permissive movements during a singledirection left turn, the circular amberindication operates in conjunction with thecircular green indication and an amberarrow is recommended to act in conjunctionwith the green arrow to indicate that theprotected left turn phase is terminating andto be consistent with the requirements forsimultaneous protected/permissive left turnsas given under HTA Subsection 1.(11). Whereprovided, the left turn amber arrow mayconsist of either a fibre optic or LED arrowwhich changes from green to amber (type 9and 9A heads), or a separate amber arrowmounted above the green arrow (type 8 and8A heads) as would be used with theflashing green arrow in this type of operation;



iv The standard indications shown in Figure1 are the only configurations that shouldbe allowed to be installed in the majorityof circumstances so that the burden ofinterpretation is not on the motorist. Inunusual conditions, it may sometimes berequired to use a non-standard signal headwhich is not shown in Figure 1. This shouldbe done only under the supervision andapproval of a very senior and fullyexperienced traffic engineer/analyst and withthe approval of the road authority; and

v Lens sizes may be either 20 cm or 30 cm forsolid green and amber circular displays in anyof the signal heads given in Figure 1. Allarrow lenses and all circular red lenses,except the red lens for the” standard” signalhead, should be 30 cm diameter.

HTA Regulation 626 Sub-section 1. (2) -Vertical Order of SignalIndications


Sub-section 1. (2) states:“Green arrow, amber arrow,circular green, circular amber, circular red and whitevertical bar indications may be used for traffic controlsignals and where they are used, they shall bearranged vertically from the bottom as follows:

right turn green arrow, right turn amber arrow, leftturn green arrow, left turn amber arrow, straightthrough green arrow, circular green, circular amber,circular red and white vertical bar.” O. Reg. 65/96, s. 1.

2. Interpretation

i Whether combined in one unit or mountedas connected sections, the relative verticallocations, from top to bottom, of the variousindications must be as specified in Table 1.

Table 1 - Relative Vertical Positions of SignalIndications

Notes:

1. The circular green indication may be replaced by a straightthrough, left turn or right turn green arrow where indicated.

2. The amber arrow direction must be the same as that of thegreen arrow below it.

3. A green indication, either a circular green or a green arrow,is mandatory on a signal head.


i For reasons of simplicity and physicalconstraints and to increase theireffectiveness, it is a recommended practicethat no more than five indications becombined in one signal head.

ii Figure 1 shows the only types of trafficsignal head configurations which shall beused due to the need to maintainuniformity in Ontario (with the exception of

White White Vertical Bar

Red

AmberAmber

GreenGreen

Amber ArroAmber Arrow

Straight Through Green Arrow

Left Turn Green Arron Green Arrow

Right Turn Green Arron Green Arrow

Transit Priority Only

Mandatory

Mandatory

Notes 1 and 3 below

Note 2 below

Note 3 below

Note 3 below

Note 3 below

Signal Indication CommentComment



Figure 1 - Traffic Control Signal Heads

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lens size which may be either 20 cm or 30 cmfor circular lenses). Exceptions to the types ofheads shown should only be used whereauthorized by a senior and experienced trafficengineer/analyst and with the approval of theroad authority; and

iii Where a white vertical bar transit prioritysection is used, the total number ofindications, including the transit section,should not exceed five.

HTA Regulation 626 Sub-section 1. (3) -Use of Circular Signal Indications


Sub-section 1. (3) states: “No traffic control signalsystem shall be operated so as to show more thanone circular indication simultaneously on the sametraffic control signal.”

2. Interpretation

i One circular indication only (green oramber or red) must be shown if no green oramber arrows are active; and

ii A red indication is not allowed to bedisplayed at the same time as a circularamber or green indication but is allowed tobe displayed at the same time with any arrowindication(s) on heads which also have acircular green.


i In practice, a circular amber indication isdisplayed immediately after the time of de-energization of a circular green indication (orgreen arrow indication where a circular greendoes not exist as in Figure Signal head types1 to 7) such that both the amber and greenare not illuminated at the same time;

ii Similarly, a circular red indication is alwaysdisplayed immediately after a circular amberindication but a circular red or green may bedisplayed after an amber arrow (Figure 1,signal head types 8, 8A, 9, 9A).

HTA Regulation 626 Sub-section 1. (4) -Two Signal Heads Required


Sub-section 1. (4) states: “Every traffic control signalsystem that is installed shall have at least two trafficcontrol signals located on the far side of theintersection from which vehicles are approaching, atleast one of which shall be located on the far rightside.” O. Reg. 65/96, s. 2.

2. Interpretation

i Every traffic approach to an intersectionrequires that two signal heads must faceoncoming traffic from the far side of theintersection. The “far side” of the intersectionis the half or side of the intersection which isacross the intersecting roadway from thetraffic approaching the signals

ii At least one signal head must be mountedat the far right hand side of the intersectionquadrant or in an equivalent location on thefar right side if there is no intersectingroadway on that side of the intersection.

iii Partial signalization or signalization of lessthan all of the traffic approaches of anintersection shall not be permitted exceptfor Intersection Pedestrian Signals.


i The signal head on the far right side isdesignated as the “primary” signal head. Thesignal head on the left of the primary head isdesignated as the “secondary” signal head.



A signal head installed in addition to theprimary and secondary signal heads is for thepurposes of aiding in signal visibility and istermed an “auxiliary” signal head;

ii Any fully protected phase, such as a left turnoperation facing type 2 signal heads, abicycle phase and so on, shall use a layoutwith two separate signal heads. In the case ofthe fully protected left turn operation, the type2 head on the traffic island is the primarysignal and the type 2 signal head on the farleft side of the intersection fulfills the need forthe secondary signal head;

iii Auxiliary signal heads shall display the sameindications, at the same times, as the primaryand secondary heads. If signal headindications are timed differently, they must beon a separate phase from the primary andsecondary heads.

iv At “T” intersections of publicly ownedroadways, any public-use driveway oppositethe terminating roadway should be treated asa highway for the purposes of traffic controlsignals. This indicates that driveways tocommercial establishments open to thepublic, schools, churches, community centres,etc. which front onto an intersection shouldbe signalized normally.

v For private driveways which front onto anintersection, it may be desirable to provide thedriveways with traffic control signals.

vi A protected/permissive left turn operationfacing type 8, 8A, 9, 9A, 10 or 10A signalheads mounted in the median traffic islandmust not utilize four signal heads on thesame side of the intersection (a maximumof three heads is permitted). This distinctionis made so that there will be no confusionwith the fully protected type of operation.The protected/permissive type of operation isintended to protect left turning traffic byoperation of a green left arrow when

opposing traffic is stopped followed by acircular green indication which permits trafficto either proceed through the intersection, toturn left when the opposing traffic allows fora suitable gap, or turn right when theintersecting roadway is clear of pedestriantraffic.

HTA Regulation 626 Sub-section 1.(4.1) -Intersection Pedestrian Signals1


Sub-section 1. (4.1) states: ”Despite subsection (4), atraffic control signal system installed at a crosswalkat an intersection for the purpose of assistingpedestrians to cross the roadway shall have

(a) at least two traffic control signals facing thedirections from which vehicles on theroadway approach the crossing; and

(b) at least one stop sign facing vehiclesapproaching the intersection from the otherintersecting roadway.” O. Reg. 65/96, s. 2.

2. Interpretation

i This subsection allows the use of IntersectionPedestrian Signals (IPS) in Ontario;

ii For the roadway being signalized, twosignal heads must face approachingtraffic in each direction. The signal headsshall be conventional ”standard” or “highway”signal heads as no turns are to be signalized,although a Transit Priority signal head may beused for turning buses;

iii The other roadway is always controlledwith stop sign(s).




i IPS applications are intended for use as analternative to Pedestrian Crossovers (PXOs)where PXOs may not be appropriate becauseof pedestrian volumes, pedestrian types(young and seniors), the Authority’s policy orroadway/intersection geometry.

ii Conventional pedestrian heads arerequired to cross the main roadway as thereare no other signal indications facing eitherdirection along the crosswalk.

iii At this time, it is recommended that the IPSshould be restricted to a single crosswalk atany intersection. The opposite side of theintersection requires a pedestrian crossingprohibition sign. (The TAC MUTCD12 indicatesuse of crosswalks on both sides of the sideroad and this type of IPS is used in someparts of Canada.)

HTA Regulation 626 Sub-section 1. (5) -Height of Signal Heads


Sub-section 1. (5) states: ”Traffic control signals, whereinstalled, shall not be less than 2.75 metres abovethe level of the roadway when adjacent to the travelledportion of the roadway and not less than 4.5 metresabove the level of the roadway when suspended overthe travelled portion of the roadway.”

2. Interpretation

i Signal heads shall not be mounted at a heightof less than 2.75 m from finished grade to thebottom of the signal head or backboard(clearance point);

ii All signal heads mounted over the lanes of aroadway, the flare areas of intersections,ramps or any other area normally travelled byvehicles must be mounted at not less than4.5 m from finished grade to the bottom ofthe signal head or backboard (clearancepoint); and

iii It is permissible to mount signal heads higherthat the minimum heights given, as long asthe height is practical for viewing bymotorists.


i The recommended practice for mounting ofany signal heads over traffic lanes is 5.0 mheight, with 5.8 m recommended for span-wire mounted signal heads. It has been foundby experience that signal heads mounted atthe 4.5 m minimum height sometimesinterfere with overheight trucks, loose trucktarpaulins or similar objects and are thendamaged. Further, span-wire mountedsignals with 8-pole rather than 4-poleconfigurations may be considered so that theentire assembly is not damaged in the eventof a vehicle colliding with a pole;

ii Primary heads should be mounted at aminimum height of 4.5 m or higher anddesirably at a height of 5.0 m regardless ofroadway posted speed;

iii Secondary heads, where mounted on the farleft and not over traffic lanes, may bemounted at a minimum height of 2.75 m orhigher and desirably at a height of 5.0 m sothat they may be seen over the tops ofvehicles from a distance. Intermediatemounting heights between 2.75 m and5.0 m are useful to improve visibility incongested urban areas where it may bedifficult to otherwise keep the secondaryheads from being masked by the opposing



primary heads. For roads of 80 km/h andover posted speed, all secondary headsshould be mounted at least at the 5.0 mclearance height; and

iv Auxiliary heads may be mounted at a heightof 2.75 m or as high as necessary to obtaingood visibility. The desirable height in mostcases is still 5.0 m. Auxiliary heads mountedat the far left of the intersection at variousheights are normally used to provide bettervisibility where the left turn lane is oftenblocked by large vehicles.

HTA Regulation 626 Sub-section 1. (6) -Ramp Metering Signals


Sub-section 1. (6) states: “Notwithstanding subsection(5), where a traffic control signal system is installedat a freeway entrance ramp as a part of a trafficmanagement system,

(a) one traffic control signal shall be located tothe left side of the roadway not less than onemetre above the level of the roadway; and

(b) one traffic control signal shall be located tothe right side of the roadway, not less than2.75 metres above the level of the roadway.”

2. Interpretation

i The low-mounted signal head referred to in (a)is required because the stop line is very near tothe signal head and it is necessary that driverscan readily see the head as the metering isaccomplished by allowing only one vehicle perlane per green indication through the location.

ii The primary or right-hand signal head is to bemounted at not less than 2.75 m to givecontinuity with normal traffic control signalsand allow for a reasonable visibility onapproach.


i This subsection refers to special “rampmetering” signals used on some freeways tocontrol the number of vehicles per hourentering the main freeway traffic. Therecommended practices and guidelines fornormal traffic control signals do not apply tothese special signals since the approachspeed is very low and because they arepredominantly used in “rush hour” to meter orgate the volumes of traffic, not to allow right-of-way to other vehicles at an intersection.

HTA Regulation 626 Sub-section 1. (7) -Don’t Walk Signals


Sub-section 1. (7) states: “A symbol ‘don’t walk’pedestrian control indication shall:

(a) be rectangular in shape and shall not be lessthan thirty centimetres in height or width; and

(b) consist of an orange silhouette of a hand ona opaque background as illustrated in thefollowing Figure:”



2. Interpretation

i Previous iterations of the pedestrian controlsignal displaying the words “DONT WALK”must not be used;

ii The colour of the “hand” shall be orange (notred as per international practice) and thehand shall present an outline figure;

iii “Opaque” shall mean black or non light-emitting.


i Minimum 30 x 30 cm pedestrian controlheads should be used;

ii Fibre optic, LED or incandescent sources maybe used if they meet the colour requirementsof ITE Publication ST-217;

iii The pedestrian control signal shall bemounted at a minimum height of 2.75 m orhigher from finished grade to the bottom ofthe housing (clearance distance) if in a singlehousing or a minimum height of 2.75m fromfinished grade to the bottom of the “walk”section of the head where used independentlyor as part of a two-section “pedestrian head”.

iv Pedestrian control indications shall be mountedso as to be visible along the crosswalk fromthe opposite side of the roadway at anintersection and shall not be mounted over thetravelled portions of roads;

v The orange hand (“Don’t Walk”) or flashingorange hand (Pedestrian Clearance Interval)must not be displayed at any time duringwhich the walking man (“Walk”) signal isdisplayed.

HTA Regulation 626 Sub-section 1. (8) -Walk Signals


Sub-section 1. (8) states: “A symbol ‘walk’ pedestriancontrol indication shall be rectangular in shape andshall not be less than thirty centimetres in height orwidth and shall consist of,

(a) in the case of a lens that cannot provide asolid symbol, an outlined symbol of a walkingpedestrian in lunar white on an opaquebackground as illustrated in Figure 1; or

(b) in the case of a lens that can provide a solidsymbol, a solid symbol of, a walkingpedestrian in lunar white on an opaquebackground as illustrated in Figure 2.” O.Reg. 213/92, s. 1(1).

2. Interpretation

i Standard 30 x 30 cm pedestrian control heads shall be used;

ii Previous iterations of the pedestrian controlsignal displaying the word “WALK” must notbe used;



iii The colour of the walking man must be abright (“lunar”) white (not green as perEuropean and some other internationalpractices) and may be illustrated either as asolid figure or as an outline;

iv “Opaque” is taken to mean black or non light-emitting;


i The walking pedestrian symbol must not bedisplayed at any time during which theorange hand (“Don’t Walk”) or flashing orangehand (Pedestrian Clearance Interval) isdisplayed;

ii Pedestrian control signals shall be mounted ata minimum height of 2.75 m from finishedgrade to the bottom of the housing(clearance distance);

iii Pedestrian control indications shall not bemounted over the portions of roads travelled byvehicles and shall be mounted so as to bevisible along the crosswalk from the oppositeside of the roadway at an intersection;

iv Fibre optic, LED or incandescent sources maybe used if they meet the colour requirements ofITE Publication ST-217 for suitable whitesymbols.

HTA Regulation 626 Sub-section 1. (9) -Mounting of Pedestrian Signals


Sub-section 1.(9) states: “The positions of the symbolpedestrian control indications referred to in subsections(7) and (8) shall be as provided in any one of thefollowing paragraphs:

1. The symbols are mounted vertically with thehand outline on top.

2. The symbols are within the same lens andare superimposed over each other.

3. The symbols are side by side within the samelens with the hand outline to the left.” O.Reg. 213/92, s. 1 (2).

2. Interpretation

i There are three ways that the standard 30 x30 cm (minimum) pedestrian control headsshall be used:

• Both displays may be integrated into a singlelens with the “hand” symbol superimposedon the “walking pedestrian” symbol;

• Both displays may be integrated in a singlelens with the “hand” symbol to the left of the“walking pedestrian” symbol; and

• The “walking pedestrian” symbol may also bein a separate head mounted below the hand.


i Single head fibre optic or LED pedestrianheads or two-section pedestrian heads withincandescent lamps may be used in lieu of thetraditional dual section head shown; and



ii The walking pedestrian(“Walk”) symbol shall not bedisplayed at any time duringwhich the orange hand(“Don’t Walk”) symbol orflashing orange hand(Pedestrian ClearanceInterval) is displayed.

HTA Regulation 626 Sub-section 1. (10) -Signals Not At Intersections


Sub-section 1.(10) states: “A traffic control signalsystem may be erected and maintained at a placeother than an intersection, in which event thearrangement of the traffic control signals shall complyas nearly as possible with the provisions ofsubsections (4) and (5).”

2. Interpretation

i This sub-section allows for the installationof:

• “Midblock Signals” where traffic controlsignals are installed solely to allow crossingof the roadway by pedestrians;

• “Traffic Signals” at the intersection of aroadway with a private driveway;

• Special traffic control signals where it isconsidered necessary to install signals for theprotection of the public. These situations mayoccur at moveable bridge spans, rail or transitcrossings, special factory equipment ormaterial moving crossings of a roadway andother locations where it is necessary tointerrupt the right-of-way of the roadway for

good reasons; and material moving crossingsof a roadway and other locations where it isnecessary to interrupt the right-of-way of theroadway for good reasons; and

• “Ramp Metering Signals” for control of trafficvolumes on ramps entering a roadway (seeSubsection for HTA Regulation 626,1.(6)); and

ii The installation of traffic signals at theforegoing locations shall give an outwardappearance to approaching motorists that isconsistent with the appearance of a normallysignalized intersection. All primary,secondary and auxiliary signal heads shouldobey the legal requirements as if anintersection where present in front of theactivity that is taking place.

3. Recommeded Practice

i The appearance of the special traffic signalsshould match the appearance of a normallysignalized intersection in the area as closelyas practical.

HTA Regulation 626 Sub-section 1. (11) -Amber Left Turn Arrows


Sub-section 1. (11) states: “A traffic control signal systemthat operates as a simultaneous protected andpermissive left turn system shall display a left turnamber arrow indication immediately after the displayof a left turn green arrow indication.”

2. Interpretation

i A simultaneous protected and permissive leftturn operation includes opposing left turnmovements which overlap but do notnecessarily terminate at the same time.



ii Where both a circular green and a left greenarrow indication are used to allow protected/permissive movements during a left turn, andwhere these are on phases occurringsimultaneously, the circular amber indicationoperates in conjunction with the circular greenindication and an amber arrow is requiredto follow a green or flashing green arrow.The left turn amber arrow shall consist ofeither a fibre optic or LED arrow whichchanges from green to amber, or a separateamber arrow may be mounted above the greenarrow.

iii Refer to Section 3 for explanation of theterms “permissive” and “protected”


i Signal headtypes 8, 8A, 9 or 9A of Figure 1 should be used for the protected/ permissive indications;

ii Flashing green and amber arrows areallowed but caution should be used in theirapplication as discussed in Section 3.5.



3. Operational Practice

3.1 Introduction

General

This part of the manual gives an overview of trafficsignal operational practice. It is required to useindustry jargon to describe various pieces of hardwareand signal operations terms and the traffic engineer/analyst is referred to the Glossary to obtain anunderstanding of any unfamiliar terms which are notexplained here.

Operational analysis requires an understanding of thetheories of traffic flow and experience in its applicationto traffic control signals. References may be found inTRB’s “Highway Capacity Manual”8 (HCM), in ITE’s“Canadian Capacity Guide for SignalizedIntersections”1 (CCG) and in the Ministry’s “TrafficControl Signal Timing and Capacity Analysis atSignalized Intersections” 25 (TCSTCA).

Standardization

Standardization of many of the aspects of trafficcontrol signal operations throughout Ontario isimpor tant from the viewpoint of motorists’expectations and hence safety.

Signal operations range from the simplest two-phaseoperation to complicated eight-phase operation at theintersections of major arterials. The local operationmay be complicated by single or dual simultaneousleft turn phases and right turn overlaps.

Modes of operations range from night flash to simplesingle plan pretimed mode to the complex multi-planwith changing cycle lengths and differing phase andinterval sequencing and timing. In all modes, theoperations shall be consistent with the establishedpractices for safety reasons.

Standardization is achieved through the application of:

• consistent determination of the need for trafficcontrol signals;

• consistent signal head use and placement;

• consistent traffic systems engineering/analysispractices in relation to selection of the mode ofcontrol;

• consistent determination of the need and typeof phasing;

• determination of the need for coordination, theneed for interconnection or the need for acentral system.

Complex items which require some standardizationin the method of solution provincially and locally are:

• the operational design of phasing requirementsand phase and interval timing;

• timing of clearance intervals;

• determination of phase time-of-day omissionsor additions; and

• determination of the need for advancedpedestrian and advanced amber displays whereintersections are close together, and forsequences required for optimization of trafficflow.



Signal Operations Report

A Traffic Signal Operations Study should be undertakenat intersections with operational problems and at newintersections being considered for signals. The TrafficOperations Study should consider the followingelements:

• collision history at the intersection;

• pedestrian volumes at various times of day;

• a turning movement study including trucksand buses;

• confirmation of through volumes of traffic;

• percentage of heavy trucks and buses;

• proximity to other intersections;

• the need to operate independently or on asystem;

The benefit/cost ratio of the proposed improvementsor new signals may also be considered.

3.2 Controller Operation

This section addresses some of the physical attributesof traffic signal controllers. Concentration is on solidstate controllers including the Type 170 controller 16

and the NEMA Standard controller 24,26. Although othertypes of solid state and electro-mechanical controllersare still widely used by municipalities, they are notdiscussed in this manual.

Modern signal controllers consist of computer printedcircuit boards with various peripheral devices tocontrol dif ferent operations. A very simplisticdescription of their operation follows:

• the Central Processing Unit (CPU) (or RemoteProcessing Unit (RPU) if the controller is in asystem) of the controller is programmed usingappropriate software to set all timed andactuated intervals and variables and to allow

the required phases for the intersection;

• the computer board sends commands via a 24Volt line to an electronic loadswitch whichallows 120 Volts to pass through or be cut offfrom the incoming line to the signal headindication lamps;

• various peripherals monitor the controllercircuits; “watchdog” circuits monitor voltagesand currents and alert the “conflict monitor”to shut down the signals and revert to “allflash” mode.

It is at the discretion of the roadway authority to selectthe type and brand of available traffic signal controllers.

The Ministry and several large municipalities use theType 170 signal controller which was developed as ahardware based modular controller. The Type 170controller is based on a hardware specification wherethe input/output specifications are all laid out for anymanufacturers to follow. Operational software mustbe purchased separately for a number of functions.

Many municipalities use the NEMA specification 24,26

controllers of either TS1 or TS2 (Type 1 or Type 2).NEMA is a functional standard where controllerfunctions that all manufacturers must follow are laidout The NEMA controller is supplied complete withthe manufacturers’ operational software which meetsor exceeds the functional specifications.

All modern controllers have connections available forconflict monitors. Conflict monitors detect theinterruption of electronic circuits due to lightning andpower surges and detect signal conflicts on green,amber and walk signals as well as the absence ofvoltage and the absence of a red signal on all of thesignal indications. Controllers shall not be operatedwithout conflict monitors.

Detailed information on controllers may be found inthe publications of the major controller manufacturersand in the NEMA 24,26 and Ministry 16 specifications.



3.3 Determination of IntersectionOperation

The mode of control used (see subsection 3.4) canhave a profound effect on the operational efficiencyand safety of any signal. The selection of the besttype of control for any location can be made onlywith full knowledge of local conditions but, in general,can be based on the following:

• the variation between peak and averagehourly traffic volumes on the main road;

• the variation between morning and afternoonaverage hourly volumes on the main road;

• the variation between morning and afternoonaverage hourly volumes on the side road;

• the percentage of the total average hourlyvolume using the intersection which entersfrom the side road;

• the percentage of large vehicles;

• special usage such as bicycles and transitbuses;

• volumes of turning vehicles;

• the seasonal variations in traffic volumes andcharacteristics;

• the length of time that the signal will be inoperation if temporary.

For any intersection, it is desirable to optimize thetraffic flow through the intersection and provide ameasure of quality of service to pedestrians, motorists,passengers, cyclists and the movement of goods. Toachieve these ends the ITE’s “Canadian Capacity Guidefor Signalized Intersections1” (CCG) recommends afour-step process which is paraphrased as follows:

1. Definition of Objectives at an Intersection:Objectives should be clearly stated and measurable.They may include minimization of average overallvehicle delay, equitable allocation of vehicle or person

delay to individual intersection approaches or lanes,maximization of vehicle capacity, control of queues,minimization of gridlock risk, minimization of vehiclestops, and so on1.

2. Analysis:

Analysis includes investigation of intersectionconditions and the determination of relevantevaluation, design or planning variables andparameters. This step includes consideration ofpreliminary signal timing and constraints and the needfor the level of detailed traffic input. Maximumefficiency and safety are derived from traffic controlsignals only where the lengths of the various intervalsare set in accordance with traffic demand for bothvehicular and pedestrian traffic.

3. Planning and Design:

This step considers future geometric features and theiterative design of the operational parameters. Thismay include field surveys for arrival flow, saturationflow, overload factor, average overall delay, averagestopped delay and queue reach, methods for whichare all defined in the CCG.

4. Evaluation:

This includes the evaluation of any changes made tothe traffic control signals for capacity related criteria,queuing related criteria and other criteria.

To achieve these ends, and because the introductionof new traffic control signals interrupts the traffic flowon all intersection approaches, it is necessary todetermine:

• measured or predicted traffic flow;

• existing or planned intersection geometry;

• cycle composition of traffic movements,phases, phase sequence, clearance intervals;



• timing design for cycle times composed oftimes for green intervals, walk intervals andclearance intervals; and

• analysis of the assigned parameters tospecific criteria that is related to intersectioncapacity, queuing, arrival traffic flow, peakingcharacteristics, and mode splits.

The foregoing factors and their analysis may be foundin detail in the Ministry’s “Traffic Control Signal Timingand Capacity Analysis at Signalized Intersections” 25

(TCSTCA) and in ITE’s “Canadian Capacity Guide forSignalized Intersections 1 (CCG)” which is primarilyfor urban conditions but may be used for anyintersection.

3.4 Selection of Mode of Control

General

The selection of the mode of control at any intersectionwill depend on several factors:

• proximity to other signalized intersections;

• operation within an existing area ofinterconnection;

• operation within an arterial or area widesystem;

• variations in traffic flows for each approachby time of day, day of week, season;

• volume percentage of total traffic volumethrough the intersection as generated by theside road;

• volumes of pedestrians crossing the mainroad; percentage of buses and heavy trucks.

The following modes may be used either for isolatedintersections (operating independently) or within aninterconnected system or a central system:

Pre-timed or Fixed Mode

A pretimed controller is one which operates within afixed cycle length using preset intervals and nodetection. A pretimed signal is a traffic control signalwhich directs traffic to stop and permits it to proceedin accordance with a single predetermined timeschedule or a series of such schedules. Operationalfeatures of pretimed signals, such as cycle length, split,sequence, offset, etc., can be changed according toa predetermined set program or plan.

This type of control is best suited where traffic patternsand volumes are predictable and do not varysignificantly. The equipment can usuallyaccommodate several plans with differing cyclelengths, splits and offsets. Potential advantagesinclude:

• consistent starting time and interval durationof pretimed control facilitate coordinationwith adjacent traffic signals. It also providesmore precise coordination than does traffic-actuated control, especially whencoordination is needed with adjacent trafficsignals on two or more intersecting streets orin a grid system;

• pretimed controllers are not dependent forproper operation on the movement ofapproaching vehicles past detectors. Thusthe operation of the controller is not adverselyaffected by such conditions as a stoppedvehicle or construction work within the area;

• pretimed control may be more acceptablethan traffic-actuated control in areas wherelarge and fairly consistent pedestrian volumesare present, and where confusion may occurwith the operation of pedestrian pushbuttons;



• generally, pretimed equipment costs less topurchase and install, and it is simpler andmore easily maintained than traffic-actuatedequipment.

Pretimed control tends to be most applicable atintersections which are part of a signal system in anurban area and where variations in volume arepredictable and control timing can be pre-set toaccommodate variations throughout the day.

Actuated Mode

An actuated signal is a traffic control signal whichservices movements based on demand. Actuatedsignals make use of detection to respond to vehiclecalls and are categorized as either semi-actuated orfully -actuated. Potential advantages include:

• traffic-actuated control may providemaximum efficiency at intersections wherefluctuations in traffic cannot be anticipatedand programmed for with pretimed control;

• traffic-actuated control may providemaximum efficiency at complex intersectionswhere one or more movements are sporadicor subject to variation in volume;

• traffic-actuated control may providemaximum efficiency at intersections whichare poorly located within progressive pretimedsystems. In these locations, interruptions ofmain road traffic are undesirable and must beheld to a minimum frequency and duration.A background cycle time may besuperimposed upon the operation to effectcoordination with nearby signals. Thisoperation is normally sluggish due to therequirement to fit into the coordinationwindow;

• traffic-actuated control may minimize delayduring periods of light traffic because nogreen time is provided to phases where notraffic demand exists;

• semi-actuated control tends to reducecollisions associated with the arbitrarystopping of vehicles.

Semi-actuated Mode

Detectors are located on the side road approachesand in the left turn lanes of the main road. Semi-actuated control is applicable to an intersection of aheavy-volume traffic arterial with a relatively lightlytravelled side road. The signal is normally green onthe main road, changing to the side road only as aresult of a vehicle or pedestrian actuation thereon oron continued actuation of the main road left turndetector (indicating that turning gaps are notavailable).

In some types of controllers, the sideroad greenintervals are of fixed duration, which may beundesirable. In the more flexible types of controllers,the duration of the side road green interval variesaccording to the traffic demand thereon, withprovision for a maximum limit beyond which the greendisplay cannot be retained on the side road even whentraffic demand on it is heavy. Upon the expiration ofthe required or maximum minor-street phase, thegreen indication reverts to the major street, where itmust remain for at least a predetermined minimuminterval. At the expiration of this minimum interval,the control is again free to respond to minor-streetactuation. The semi-actuated control mechanismreceives no actuation from traffic on the main road,and therefore may frequently assign the right-of-wayto the side road at the most inopportune time formain road traffic. Hence the effective use of semi-actuated control is limited to intersections with verylightly travelled side roads and to intersections incoordinated systems where main road progressioncan be assured.

In a coordinated system, side road actuation can belimited to a” window” of time during a fixed cyclewhich best accommodates main street progression.



In a semiactuated controller, signal indications are notof fixed length but are determined by the side roadchanging traffic flow at the intersection. This canoccur within a fixed cycle length, or within specifiedminimum and maximum limits of main and side roadgreen indications. In some cases, certain intervalsmay be omitted when there is no actuation or demandfrom waiting vehicles or pedestrians. In semi-actuatedoperation, the main road may have the “mainroadped recall” feature activated. In this mode, the walksignals along the main road are on as well as themain road greens and pedestrian movements on themain road are therefore facilitated. A commonvariation is the rest mode for the main road green/walk with the minimum walk timed out and delayrepresented by the flashing Don’t Walk (FDW). Sideroad actuation calls will send the controller unit intothe FDW pedestrian clearance interval. Forcoordinated systems use, the main road pedestriansignals may rest in “Don’t Walk”.

Fully-actuated Mode

This type of control requires detection on allapproaches of both the main road and the side road.Fully-actuated control should be selected forintersections where failure to take all traffic demandsinto account will materially impair the efficiency oftraffic control. Fully-actuated operation is suitable foruse at:

• intersections where the traffic volumes of themain road and the side road are more or lessequal but with sporadic and varying trafficdistribution;

• locations where turning movements areheavy only during specific periods and lightthe rest of the time;

• high speed locations where there is a need toavoid “dilemma zone” problems.

Where, in rural situations, traffic volumes on both themain road and side road are similar, presence/extension loops may be installed at the stop lines onboth roads and the signal phase rests in the greendisplay of the traffic direction last being served orrecalls to main road green. The operation may beused in coordinated systems with a background cyclesuperimposed upon the operation to ef fectcoordination with nearby signals.

A variation is used on roadways posted at 80 km/hor greater where the sideroad is actuated but the mainroad rests in green, and has extension loops set backfrom the stop line. The long distance or “passage”loops are located at an upstream distance as given inSection 4. The purpose of the passage or “extension”loops is to add to the main road green time to allowthe higher speed main road traffic to enter theintersection one second before the amber signal isdisplayed. This aids in decisions within the “dilemmazone” and allows motorists to continue through theintersection without hesitation. If the traffic on themain road is heavy, the extension loops will beregistering calls regularly and extending the main roadgreen time, until a maximum programmed time limitis reached. At that time, main road green is said tohave “maxed out” and the side road phases areinitiated regardless of the main road traffic.

System Operation

General

A system can vary from two or more interconnectedcontrollers to large centralized computers controllingthousands of intersection controllers. Two or moreintersections may be controlled as follows:

• slave controllers at each intersectioncontrolled by a field master controller.



• controllers at each intersection controlled by acentral computer (normally a PC for smallsystems); each controller can have its owndedicated connection to the central computeror a group of controllers can be connected tothe central computer via a master contoller.

Signal systems, except for systems using trafficadaptive software such as SCOOT (Split Cycle OffsetOptimization Technique), use a common cycle lengthand have a definite offset relationship between theirmain road greens (or advanced or delayed greens)for each major section of road. Any system whichaccommodates traffic progression offers the followingadvantages over isolated/ independent operation:

• traffic normally moves in tight groups orplatoons, with clear gaps between platoons,which may be utilized for vehicle orpedestrian crossing times at sideroads or atsecondary intersections or entrances betweensignalized intersections;

• stops and startup delays for main road trafficare reduced and overall delay is generallydecreased, although this may increase delayon the sideroads;

• increased intersection capacity by decreasingthe volume of queuing vehicles and therebydecreasing headways and startup delays;

• reduced collision rates by reducing the speeddifferential between individual vehicles;

• reduced rear-end collisions by reducing theneed to stop.

• reduced fuel consumption, noise and airpollution by reducing the number of stopsand delays;

• systems with central communications offermaintenance benefits by reducing field visitsrequired to update timing plans as well as byproviding quicker response through earliernotification of equipment malfunctions.

Coordination

Systems are normally initially started for intersectionsin the Central Business District (CBD) but inevitablyexpand outwards to major arterials in outlying areas.The problems of both types of areas are different andare sometimes treated differently with respect to thecontrolling software used and the number of plansper day that are required. As well, CBD systems arenormally based on grid networks and systems inoutlying areas may be local arterial coordinationsystems.

Where an arterial has multiple sets of signals but thesignalized section is itself isolated from other sectionsof signalized roadway, a coordinated interconnectedsystem should be considered for local operation whereintersections are less than 1.0 km apart for postedspeeds less than 80 km/h and less than 1.5 km apartfor posted speeds of 80 km/h and over.

In such a simple coordinated system, different timingplans may be selected on a time of day basis or on atraffic responsive basis. For traffic responsive systems,vehicular volume and density (occupancy) aremeasured by detection devices in the roadway andappropriate cycle lengths and offsets are chosen forprogramming into the master controller.

In a more complex traffic adaptive system the trafficis continually travelling over loops placed downstreamof all intersections and the central computer calculatesand applies the new cycle length and offset requiredto accommodate the progression of the platoons.

Pretimed control is normally used for simpleinterconnected systems and on minor centralizedsystems. Pretimed operation can promote theformation of tight platoons of traffic where goodprogression is possible. This is because vehiclesentering the coordinated route will usually be releasedfrom the first intersection with a high probability ofgetting a green signal at all downstream intersectionson the route. However, actuated control may reducesystem delays if a significant proportion of vehicles



join the route from side roads or accesses along theroute, and arrive randomly at intersections within theroute. Actuated control will simulate pretimed controlwhen vehicle volumes are high enough on the sidestreet that continuous vehicle actuation causes theside road to go to the maximum green time allowed.

Actuated control has some advantage for use oninterconnected intersections which are not beingcontinually actuated at the side roads. In these cases,some progressions, which are less than optimal dueto the distance between intersections, can be madethrough the intersections except during times whenactual transfer of right-of-way is required. Controllersoperating in actuated mode may be fitted with acoordination unit to interconnect with pretimedcontrollers.

Design and analysis software is available to performcoordination and network analysis. The coordinationis calculated to progress traffic through a particularset of traffic signals along an arterial by using an offsettime to each intersection for the beginning of mainroad green. Normally preference is given to thedirection with higher traf fic demands whendetermining offsets. The extent to which two-wayprogression can be achieved is a function ofintersection spacing, cycle lengths, and the numberof signals in the control area. When controlling a gridnetwork, balancing of directional preferences is moredifficult than for single arterials but similar principlesare used.

Modes for Isolated Operation

Table 2 (page 26) may be used as a guide for theselection of the type of controller operation at anyisolated intersection subject to variation in the localconditions. In Table 2, the 20% volume variation istaken as the critical value since with average volumes,this variation would require a change in cycle lengthwhich cannot be accommodated with single planpretimed operations. Actuated control may be used

to advantage at complex intersections wheresimplification is not possible and where a minormovement must be accommodated since it can bearranged for one or more phases to be omitted whennot required.

3.5 Phase Determination

General

The number of phases required for efficient operationwill depend on the physical characteristics of theintersection, the equivalent through volumes and theequivalent volumes of turning movements takingplace. The least number of practical phases shouldalways be used to reduce the “lost time” due toclearance intervals between phases.

Guidelines are primarily found in the Ministry’s “TrafficControl Signal Timing and Capacity Analysis atSignalized Intersections” 25 (TCSTCA) and ITE Canada’s“Canadian Capacity Guide for Signalized Intersections”(CCG1).



Where the volume of vehicular or pedestrian trafficentering or crossing one or more approaches issufficient to impact the operation of the intersection,though not sufficient to justify a completely separatephase, one or more of the normal phases may besplit or programmed as a “subordinate” phase toprovide an interval within the associated or parentphase. An advanced green exhibited with a throughmovement is such a case.

The number and type of phases required will be largelydependent on the left turn volumes-and-intersectiongeometrics. An analysis of the left turning volumesand intersection geometrics will determine whatphases are required. The number of phases and theirsequence will constitute the cycle structure.

Standard Movements

General

It is recommended that the standard traf ficmovements, as identified by number, be used for thetype of controller to be utilized.

The type 170 controller 16 and the NEMA typecontroller24,26 use similar but different methods ofmovement identification.

Traffic Movements for Type 170 Controllers

Type 170 controllers identify traffic movements asshown in Figure 2. The “F” designates a “faze”(movement) number and “P” designates a pedestrianmovement number. The following convention is used:

• The through fazes are even numbers startingwith faze 2 (always on the main road) ineither the northbound or eastbound locationand progressing clockwise around theintersection;

• the left turn fazes are odd numbers, startingwith faze 1 (always on the main road) in thesouthbound to eastbound or the westboundto southbound location and progressingclockwise around the intersection;

• faze 2 always opposes faze 1. Odd numberfazes are always left turn movements andeven numbered fazes are always throughmovements.

Table 2 - Controller Operations Types for Isolated Operation



Traffic Movements for NEMA Type Controllers

NEMA type controllers identify movements as indicatedin Figure 3. The “P” designates a pedestrian movementnumber. The following convention is used:

• the through movements are even numbersstarting with movement 2 (always on themain road) in either the northbound oreastbound location and progressing counter-clockwise around the intersection;

• the left turn movements are odd numbers,starting with movement 1 (always on themain road) in the southbound to eastboundor the westbound to southbound location andalso progressing counter-clockwise aroundthe intersection;

• movement 2 always opposes movement 1.Odd number movements are always left turnmovements and even numbered movements arealways through movements.

Interval Sequence

The interval sequence occurs in a predetermined order,within any phase.

A phase is composed of two or more intervals consistingof specific displays of green, green arrow, amber, amberarrow and all red indications which may provide timingfor one or more subordinate or split phases. Forexample, if there are no separate left turn displaysprovided, the operation is a simple “two phase” one(abbreviated as ”2ø”) and through greens proceedconcurrently (they are “tied together”) followed byambers, all red clearance interval and then the sideroad through movements concurrently. The traditionalnormal sequence of phases with left turn indications,as may be used at isolated intersections, is indicated inthe following phase “diagrams”. Opposing movementsmay be considered interchangeable depending onactuation or intervals may be skipped or tied together.

Phase Diagrams

It is essential that phase diagrams on the approvedsignal plan show the following information in order toavoid any confusion or misunderstanding at a laterdate:

Figure 2 - Type 170 Fazes

Figure 3 - NEMA Movements

OR

MAIN ROAD

N

N

4P

F4

F5F2

F3 F8 8P

6P

F6

F1

2P

F7

SID

E R

OA

D

4P

2P

F2

F5 F6

6P

F1

OR

F8 F3

F7 F4

SID

E R

OA

D

MAIN ROAD

N

N

8P



• each lane should be shown;

• the signalled movements should be shown insolid lines with the appropriate movementnumbers;

• the movements within each circle shouldrepresent only those taking place within thephase;

• the connecting lines between the phasecircles should be solid with arrows indicatingthe permitted direction of phase change;

Typically, in the following sections, all phasediagrams are specific to the application and mustbe individually devised for each intersection. Theexamples shown use “permissive” and “protected”movements.

In a permissive mode, the left-turning motorist ispermitted to turn during the normal circular greendisplay and can complete the turn if adequate gapsoccur in opposing traffic. The motorist must yield toopposing traffic and pedestrians crossing the roadway.The left-turning vehicle can clear the intersection onthe normal amber indication after yielding to anyopposing through vehicles and pedestrians clearingthe intersection 23.

In a protected mode, no conflicting traffic is permittedto proceed during a protected left-turn movement.The left-turning motorist is given a signal display whichprovides right-of-way for the left-turning vehicle overconflicting traffic. Pedestrians are prohibited fromcrossing the path of the left-turning vehicle duringthe protected left-turn movement. The protected leftturn is indicated by a left arrow display with anaccompanying sign or by a flashing circular green ora solid or flashing left green arrow.

Permutations and combinations of different modesof left turns are possible. For example, a permissivemovement may be applied to one approach and aprotected one to another within the same intersection.

In some cases, simultaneous left turns are used whereleft turns from opposing directions are allowed to maketheir turn at the same time during protected left-turnmovements. The simultaneous left turns are indicatedby left arrow displays facing each opposing lane ofturning vehicles. For true simultaneous operation, bothof the opposing left-turn phases start and stop at thesame time. Because it is common to apply detectionto both lefts, the term “simultaneous” is also used forthe case where the two left-turn indications may startand end at different times.

Two Phase Operation

A simple two phase operation is satisfactory for manyintersections. In this operation, the controller simplyalternates between main road and side road greensunder any mode of operation. Figure 4 shows thephase diagram.

Three Phase Operation

With the addition of a left-turn signal on any approach,the operation becomes a 3 phase one as shown inFigure 5 in which movement 5 is the advance green(any of the other three can be selected, in propersequence). Note that this operation would be classedas “protected permissive” as the left-turn green signaldisplay would be a left-turn arrow type 8, 8A, 9 or9A, a flashing circular green or a flashing green arrowfor the protected left-turn movement. Left turns wouldalso be permitted after the left-turn display hasstopped.

Multiple Phase Operation

The number of phases may be increased to provideup to 8 phases where analysis indicates that they arerequired to serve the equivalent traffic volumes.



Figure 5 - Three Phase Diagram

For more complete discussions of phase diagramsand allowable phases and interval sequencingwithin the dual ring configurations, the engineer/analyst should consult the printed materials ofthe major controller manufacturers, the Ministry’sElectrical Design Manual 2 and TCSTCA 25.

For demonstration purposes, six phase diagrams withprotected/permissive simultaneous left turns on theside road approaches and fully protected simultaneousleft turns on the main road are shown in Figure 6.The following should be noted:

• for clarity, stopped traffic is not shown;

• the operation shown will operate with amaximum of six phases since only phase ’B’or ‘C’ on the main road and phase ‘F’ or ‘G’on the side road may occur in any one cycle.

2

2

2P

2P

PHASE A

PHASE A

PHASE B"RECALL PHASE"

PHASE C

PHASE C

8

5

8P

8

8P

NEMA TYPE

170 TYPE

6

6P

2

2P

4

4P

2

2P

5 6

6P

PHASE B"RECALL PHASE"

4

4P

Figure 4 - 2-Phase Diagram



170 Controller NEMA Controller

Figure 6 - Multi Phase Diagrams With Fully Protected Operation on the Main Road and Protected/Permissive Operation on the Side Road

Pedestrian Phases

General

In normal applications, the pedestrian timing intervalrequirements will sometimes exceed the green timesrequired for vehicular movements and will override thevehicle timing. Pedestrian signal indications shouldfollow the following sequence:

• Steady Hand Outline (“Don’t Walk”) shall bedisplayed with the corresponding throughphase reds and with any conflicting protectedturning movements. This indication may alsobe displayed during the amber display;

• Walking Pedestrian (“Walk”) shall be displayedonly when the corresponding throughmovement green indications are displayed. TheWalking Pedestrian indication does notnecessarily have to be displayed with the green

at actuated intersections (where a pushbuttonactuation is required) as this allows for the useof less vehicular green time during cycles whenno pedestrians are waiting to cross; and

• Flashing Hand (“Flashing Don’t Walk”, FDW)should be displayed after every WalkingPedestrian indication as this is a clearanceinterval required to warn pedestrians of anupcoming steady Hand Outline indication. Itis permissible to continue the FDW throughthe amber and all-red clearance intervals asthis allows more time for pedestrians;however, it may not allow sufficient vehicleintersection clearance opportunity.

Exclusive Pedestrian Phases

Exclusive pedestrian phases are normally required onlywhere the volumes of crossing pedestrians areextremely high and safety is impaired by the use ofnormal pedestrian display intervals which parallel the(vehicle) signal head operations. Should volumes of

"RECALL PHASE""RECALL PHASE"



pedestrians become severe, an ”all-cross” phase can beapplied where only pedestrian Walk signals are displayedin all directions (including “corner to corner” diagonallyacross the intersection) and all vehicular trafficindications are on red. This method is normally onlyused on downtown streets of the ”street mall” naturewhere traffic avoids the areas due to the congestion inany event. Exclusive pedestrian phases offer advantagesas follows:

• eliminates friction between pedestrians andright-turning vehicles;

• potentially reduces delays to motorists incurb lanes.

Disadvantages are:

• increases delay for all pedestrians;

• increases potential for pedestrians to disobeysignals;

• increases delay for vehicles in theintersection which are not the first vehicle inthe curb lane (for right turn on red) becausetime must be allowed to clear the fullintersection of pedestrians;

• disruptive to signal coordination becauselonger cycle lengths and shorter green timesare normally required;

• increases queue lengths for all intersectionapproaches and turning lanes, potentiallycausing queue spillover;

• potentially exceeds storage space availablefor pedestrians waiting on the sidewalks;

• no right hand turns on red.

Pedestrian Signal Operation

Pedestrians facing the Walking Pedestrian indicationmay enter the crosswalk and proceed in the directionof the Walk display. For the pedestrian intervalclearance, the Hand Outline should be a flashing

indication. The clearance interval should terminate(and change to the steady Hand display) at the onsetof the accompanying vehicular amber but in practiceis allowed to continue until the beginning of the all-red. Pedestrians facing the flashing Hand Outline shallnot start to cross the roadway in the direction ofindication. Pedestrians who have commenced thecrossing while facing the Walking Pedestrianindication may complete their crossing and have theright-of-way over traffic to do so. The flashing HandOutline should be flashed at a rate of not more than60 nor less than 50 ON and OFF flashes per minute,with the length of each ON period approximately equalto the length of each OFF period. Pedestrians facingthe steadily illuminated Hand Outline indication shallnot enter the roadway in the direction of the indication.

Left-Turn Phase Justification

General

Left-turning movements are affected by turning cars,lane configurations, pedestrian movements, opposingtraffic flow, the width of the intersection and thephasing of the traffic control signals.

Except for the case of a fully protected left-turn phase,left-turning vehicles will take more time to clear theintersection than the straight through vehicles becauseof the opposing traffic. The left-turning vehicles mayalso block through vehicles in their lane unless aseparate left-turn lane is provided with adequatestorage to handle the number of arriving vehicles lessthe number of turning vehicles per cycle.

The contents of this subsection assume that an adequateleft-turn lane can be provided. Where the left-turningmovement is combined in a lane with the straightthrough traffic movement, shifts of the straight throughtraffic from this lane to the other through lanes mustbe taken into account. This case is treated in theTCSTCA25.



Approximation

A simplified method using traffic volumes may be usedto initially analyze the need for left-turn phases atplanned or existing signalized intersections. Themethod is as follows:

A left-turn phase may be justified:

i If the left-turning vehicles are not findingsuitable turning gaps and volume exceeds atleast two vehicles per cycle not turning andthe Level Of Service at the intersection willnot be jeopardized; or

ii If the left-turning volume plus the opposingvolume > 720 vph; or

iii If a field check shows that vehiclesconsistently require more than two cycles inthe queue in order to turn left.

Methods of Analysis

There are several methods used in Ontario todetermine justification for separate left-turn phases.Two of these approaches are discussed as follows:

1. Capacity Analysis Method

This method is given in the TCSTCA25 and isabbreviated and paraphrased here. The method isuseful for planning of new signals.

When separate turning lanes are used, the equivalentvehicle volume of the turning lane should becompared to the equivalent vehicle volume of theother lanes to determine the critical lane volume whichjustifies a separate left-turn phase.

The threshold capacity of a left-turn lane can be stated25

as [1400 G/C - Vo] taking into account V

o, the opposing

volume of traffic. Left-turn volumes greater that thethreshold capacity require a left-turn phase. V

o includes

right-turning traf fic if there is no right-turnchannelization. G is the green time for the opposingflow in seconds and C is the cycle length in seconds.If there is more than one opposing lane (not countingopposing left-turning vehicles if they have a separatephase), the left-turn lane capacity of [1400 G/C - V

o ]

must be modified by a factor “f” to take into accountthe effect of multiple opposing lanes as given in Table3. The opposing volume, V

o, should be modified by

the (f) factor according to the number of opposinglanes

Source: ref. 23

The left-turning volumes normally include an allowanceof two vehicles per cycle turning on the amber interval,clearing the intersection.

The capacity of the left-turn lane during the permissivestage (no separate left-turn phase) is given by:

cLt =1400 G/C - (f) V

o + Lt

a

where:

cLf = the capacity of the separate left-turn lane

during the permissive stage of the phase invehicles per hour;

(f) = the volume adjustment for the opposingnumber of lanes (Table 4);

Vo = total opposing traffic flow, vph including

through lanes, shared lanes and right-turnlanes where right-turn channelization doesnot exist;

G/C=Green time interval for the opposing flow /cycle length (seconds).

Table 3-Capacity Factor for Opposing Lanes



Lta = 7200/C vph and is the number of vehicles

turning left on amber assuming 2 vehiclesper cycle.

If the calculated value of cLt is less than the actual

number of left-turning vehicles), then a separateleft-turn phase may be justified. If the opposingand the left-turning traffic is mixed with transit busesand trucks, the volumes in the formula should beadjusted by the heavy traffic percentages. TheTCSTCA25 provides nomographs for the solution ofthe problem.

2. Left-Turn Delay Method

This method is one developed by Metro Transportationin their “Left-Turn Phase Criteria” study9. The methodis useful for existing intersections and consists of thefollowing basic steps:

A. Needs Criteria:

a. If potential intersection benefits with no delaystudy needed -go directly to Impacts section ;

b. Average >= 2 LT per cycle in an hour withinthe study period;

c. >=10% of LT have one or more cycle delaysin an hour within the study period;

d. >= 5 vehicles per hour have one or morecycle delays in an hour within the studyperiod;

e. Any of:

e1: LT study period collisions total 6 or moreover the past 5 years or;

e2: LT 24 hour study period collisions total20 or more over the past 5 years or;

e3: LT study period collisions total 2 or morein the most recent single year or;

e4: LT 24 hour study period collisions total 5or more in the most recent single year or;

e5: > 2 evasive actions per hour observed inan hour within the study period.

f. > 2.5 LT sneakers per cycle on average over anhour within the study period (impacts nextphase);

g . LT queue blocks through lane > 30% ofcycles for multiple through lanes, (busiesthour) or LT queue blocks through lane > 10%of cycles for single through lane, within anhour in the period;

h. More than 2 in-service transit vehicles perhour in the LT traffic in an hour within thestudy period;

i. There was a previous request regarding thesame LT movement within the last 18months.

Consider Left-turn phasing if a. or (b.& c.) or (b.& e.)or (b.& d.) and any one of f., g., h. or i. is/are true.

B. Impacts

Recommend new left-turn phasing if needscriteria are met UNLESS:

a. Green time is not available or cycle lengthincrease is not acceptable;

b. If LT queue spillback is one of the applicablecriteria, check to see if lengthening the left-turn bay is possible, cost effective, and wouldreduce the problem;

c. There is a policy reason why LT phase is notdesirable (e.g. LT phase will encourage left-turn traffic through a neighbourhoodprotection scheme, or from streetcar tracks);

d. Quality of signal progression is greatlydecreased.



Determination of the Type of Left-Turn Phase

General

Once it has been determined that a left-turn phase isrequired, it is necessary to assess the type ofoperational characteristics that are required. Theserange from the relatively simple and commonprotected/permissive advanced green on oneapproach only (using type 8, 8A, 9 or 9A signalheads), to the complex multiple phase operation withleft-turn phases in all directions. The traffic engineer/analyst must choose the type of operation and shouldconsider the following items:

1. If there is no requirement for an opposingleft-turn phase, during the plan underconsideration, and if the capacity analysisindicates that a single left-turn lane willsuffice, the protected/permissive type ofoperation should be considered as it is thesimplest and most economical to implement;

2. If a geometric or visibility problem exists atthe intersection, consideration should begiven to a fully protected left-turn phase. Thistype of operation may also be consideredwhere the left-turn movement is predominantand the green interval for straight throughtraffic is governed by the opposing trafficflow;

3. Where capacity analysis indicates that dualleft-turn lanes are required, from equivalentleft-turning volumes or from queue endrequirements, fully protected operation shouldbe considered. Protective/permissiveoperation may be examined for use with dualleft-turn lane operation only when:

• geometry of the intersection and approachesallows proper turning treatment;

• opposing through volumes are very low andit is considered that motorists will not haveproblems judging gaps in opposing trafficfrom the most right-hand left-turn lane.

Where dual left-turn lanes are needed, the morecommonly used fully protected operation should beconsidered as left-turning vehicles have a completelyseparate phase;

4. Simultaneous left-turn operations should beconsidered wherever both opposing left-turnlanes require separate phases. The left-turnphases may be operated in the protected/permissive mode or the fully protected modewith the latter being preferred where dual left-turn lanes are used or where high volumesmay cause motorist distraction such as at anintersection with requirements for four wayleft-turn phases.

Recommended practice for simultaneousprotected/permissive left-turn operation, withsingle left-turn lanes, uses type 8, 8A, 9 or9A signal heads. Recommended practiceprovides for a fully-protected left-turnoperation to use separate left-turn signalheads. A sign showing “Left-Turn Signal” is arecommended part of a fully protected left-turn operation and should be located to theleft of the median pole between the left-turnsignal head and the pole or as close to thesignal head as practical.

5. Delayed green or permissive/protectedoperation should be considered only wherethere is no opposing left-turn movementwhich would create an unsafe trap situation.These operations are required to fit smoothtraffic flow into a coordinated system.



Types of Left-Turn Phasing

The figures shown in this section are sufficient only toshow the left-turn parameters. A more completetreatment of display diagrams may be found in theTAC MUTCD12. Additional amber, clearance and othertraffic movement phases beyond those shown arenormally required. The material presented here isrecommended practice for the conditions given.

1. Advanced Green, Single Direction

This type of signal phasing gives a protected/permissive left-turn movement in one direction Theleft-turning vehicles are first given a protected intervalon which to turn with opposing traffic stopped. Theassociated through and right-turning vehicles are alsoallowed to proceed during the protected left-turnphase. After the protected movement terminates with

Figure 7 - Protected / Permissive Intervals

a clearance interval, the opposing traffic is releasedwith a normal circular green ball display. The left-turning vehicles are still permitted to turn; however theymust yield to any opposing traffic.

The use of signal heads 8, 8A, 9, 9A, 10 and 10A arepreferred for protected/permissive advance greenoperations. The amber arrow is optional but isrecommended for consistency and to ultimatelyadhere to TAC’s requirements. Alternatively, the useof the circular flashing advanced green and arrowflashing advanced green is allowed under Section 144(13) the HTA.

This type of phasing is shown in Figure 7.

9 99



Figure 8a - Protected / Permissive Simultaneous Left-Turn Operation

2. Protected/Permissive SimultaneousLeft Turns

This phasing gives left-turning vehicles from opposingdirections a protected left-turn phase at the same time.No other conflicting vehicles are allowed to enter theintersection during the simultaneous protected left-turn phase. After the simultaneous protected left-turnphase has been terminated, the left-turning vehiclesare permitted to turn through opposing traffic ifadequate gaps are available.

When the left-turn lanes are separately actuated, theprotected left-turn phase from one direction mayterminate before the other left-turn phase. When thisoccurs, the associated through and right-turn vehiclesare allowed to proceed with the one remainingprotected left-turn movement. Also, if there are noopposing left-turning vehicles during a cycle, the

9 99

9

1. Advance green arrows on protected left-turn interval. All other indications are red.

2. Where actuation on one of the left turns stops, the facing indications go through the amber clearance while the opposing left turn continues.

3. Terminating left turn faces red display. Opposing left turn continues.

9 9



opposing protected left-turn phase can be skipped andthe operation during that cycle will be similar to anadvanced green. Figures 8a, 8b and 8c show thebasic intervals.

3. Fully Protected Simultaneous Left Turn

This operation provides left-turning vehicles with theirown traffic control signal heads. Left-turning vehiclesfrom opposing directions are given a left-turnindication at the same time. No other conflictingvehicles are allowed to enter the intersection during

the left-turn phase. In normal Ontario practice, theturn movements are usually programmed to giveoverlapping simultaneous lefts. The left-turn intervalsare terminated with their own clearance displays andleft-turning vehicles are not permitted to proceedwhen the opposing through traffic is given a greenindication. The opposing left turns may terminate atdifferent times. To assist the motorist in recognizingthe Type 2 left-turn signal heads a “Left Turn Signal”sign should be placed adjacent to these heads. Thistype of operation is used where the visibility of vehicles

Figure 8b - Protected / Permissive Simultaneous Left Turn Operation... Continued

9 99

4. Opposing through movement starts up.

5. Opposing left turn goes through amber clearance

6. Protected left-turn phase ends

9 9 9



Figure 8c - Protected / Permissive Simultaneous Left Turn Operation ... Continued



Figure 9 - Fully Protected Left-Turn Operation(Note: Not all intervals shown)



Figure 10 - Extended Green Intervals(Note: Not all intervals shown)

making left turns to the opposing traffic, or vice versa,is a concern or where distractions caused by turningtraffic are a concern. It may also be used where theopposing traffic approach has high volumes resultingin poor availability of gaps in the opposing traffic forpermissive left turns. This type of operation shouldalso be used on high speed roads where visibilityproblems due to geometry or collision problems exist.Double left-turn lanes may require this type of phasing.Figure 9 shows the basic intervals.

4. Extended Green, Single Direction

This phasing gives a permissive/protected left-turnmovement. Left-turning vehicles are first permittedto turn after yielding to opposing vehicles during anormal green ball display. They are then provided witha protected left-turn phase in one direction after theopposing approach has been terminated with acircular amber and circular red display. The associatedthrough and right-turn movements are allowed toproceed during the protected left-turn phase. Thistype of phasing can only be used at locationswhere there is no opposing left-turn movement,

and Permissive Left Turn during first part of green interval.

3. Extended Protected Green Arrow Interval (to be followed



for example, at “T” intersections and at 4-Legintersections where the opposing left-turnmovement is prohibited. If used otherwise, anopposing left-turn vehicle may be trapped in theintersection while waiting for a gap since he expectsopposing traffic to receive an amber display when hedoes. Figure 10 shows the basic intervals.

5. Separate (Exclusive) Phasing

This type of phasing allows one traffic approach tothe intersection to proceed while the traffic on all otherapproaches is stopped. All movements on theseparate phase approach including left turns arepermitted to proceed through the intersection.

This method which is typically used with either/orshared lanes is generally inefficient but offers a veryeffective way to eliminate collisions involving left turnswith opposing through traffic.

Figures 11a and 11b illustrate the basic intervals forthis type of operation.

6. Lagging Fully Protected SimultaneousLeft Turn

This operation is similar to that for the “Fully ProtectedSimultaneous Left Turn” as described previously exceptthat left-turn movements are given their protectedphase after the through traffic phase.

Figure 11a - Separate (Exclusive) Phasing



Figure 11b - Separate (Exclusive) Phasing

If there is periodically insufficient left-turn storage spacefor the subject movements, through movements canbe blocked during the solid green phase by left-turnqueue spillover. Operating the left-turn phase beforethe through phase would be preferable in this casebecause any queue spillover could be cleared prior tothe through green, and additional motorists could enterthe left-turn lane.

However, this method is seldom used since left-turningdisplays are normally brought on before the throughtraffic indications. It is recommended practice thatthe use of this type of operation be restricted to thatrequired to minimize delays to large volumes of turningtraffic in a system where good progression

requires the operation because of the proximity of othersignalized intersections. This operation can also beused with fully actuated operation and fully actuatedleft-turn phases if there is no actuation on the sideroad and actuation occurs for the left-turn movement.

6



3.6 Timing

General

In order to estimate the timing required for intervalsand phases, it is necessary to have on hand reasonablyup-to-date or predicted traffic volumes per movement.Prior to deriving the traffic control signal timing,vehicle and pedestrian traffic flow and equivalentvolumes must be analyzed as stated in Subsection 3.Traffic demand analysis will determine the optimuminterval timing to achieve safety and maximize trafficflow efficiency.

Guidelines are primarily found in the Ministry’s “TrafficControl Signal Timing and Capacity Analysis atSignalized Intersections” (TCSTCA25) and ITE Canada’s“Canadian Capacity Guide for Signalized Intersections”(CCG1).

During the determination of equivalent traffic volumesin accordance with the principles of the CCG1 or theTCSTCA 25, care should be taken to apply appropriatefactors for turning vehicles, heavy vehicles (trucks andbuses) and approach lanes. The number of usablelanes may also vary at different times of the day forurban conditions as there may be on-street parking,bus stops, HOV lanes, etc. present. The referencedocuments use the theory of intersection and lane flowratios to determine minimum and optimum cycle times.The flow ratios are related to capacity and delay andlost time per cycle.

The analysis of the interval and cycle timings are moreconvenient to carry out when a rough idea of thetiming is calculated first.

Minimum Interval Timing

Motorists do not expect an immediate termination ofa signal display that has just started.1 Table 4 showsguidelines for minimum interval timing values:

Calculation of Clearance Interval Timing

General

The required clearance time for any through movementphase is related to the approach operating speed, themotorists’ perception and reaction times, the crossingwidth of the intersection and the average decelerationrate of the vehicles. Amber times are set so thatmotorists can reach the intersection while in thedilemma zone. The all red times are set so that vehiclesjust crossing the stop line have sufficient time to clearthe intersection. It is generally accepted that the postedspeed is used to ensure safe clearance times.

Table 4 - Minimum Timing Intervals



Amber and All-Red Clearance Intervals

The total clearance period is separated into the amberinterval clearance and the All-Red interval clearance.The clearance period may be expressed as: 1,23

clearance = y+ r=[t+ (V/2a+ 70.6g)]+[3.6 (W+l )/V] Amber + All-Red

Where:

y = the amber interval clearance(s);r = the all-red interval clearance (s);t = 1.8 seconds perception and

reaction time (s) for posted speedsof 80 km/h or greater and 1.0seconds for posted speed < 80km/h;

V = approach operating speed (km/h);

70.6 = factor of 2 x acceleration of gravityin km/h/s;

g = % grade/ 100;a = average deceleration rate (11 km/

h/s used);l = 6.0 m taken as the length of the

average passenger vehicle;W = width of the intersecting road (m)

to be crossed from the near sidestop line to the far side curb lineor the far outside edge of thecrosswalk where used;

3.6 = factor to convert km/h to m/s.

The amber interval y = t + V/2a+ 70.6g indicatesthat the right-of-way is about to be changed andprovides sufficient time for the approaching motoristto travel the Stopping Sight Distance.

The all-red interval r = 3.6 (W +l)/V represents thetime required to provide a safe passage across theintersection for vehicles entering the intersection ator near the end of the amber interval. In the interestsof standardization, the all-red interval should be usedat all signalized intersections.

The amber and all-red clearance intervals timing, atlevel approach grades, is given in Table 5 for 1.0 and1.8 seconds perception plus reaction time. The 1.0second value is used by many municipalities and the1.8 seconds is used on rural roads, King’s Highwaysor higher speed roads.

Clearance for Left-Turn Signals

Where the protected/permissive mode of operationin a left-turn lane is used, it is not required to providea Level of Service (LOS) greater than LOS E * regardlessof the LOS on the through lanes. Queuing is normaland two vehicles are considered to be able to clearthe intersection on the amber. Since the speeds arelower for the left-turning vehicles and the time acrosshalf the intersection is also lower, engineering/analystjudgement should be used to ensure safety. A greenclearance or an amber arrow clearance of 1.5 to 3.0seconds must follow the left-turn green (green arrow,or fast flash green ball) before the opposing traffic isreleased. An all red of 1.0 to 1.5 seconds may beused after the amber arrow if additional clearance isrequired.

Where the fully protected mode of operation in a left-turn lane is used, a nominal amber clearance time of3.0 seconds should be used followed by a 1.5 secondto 2.0 second all-red to complete the clearance ofany left turning vehicles left trapped in the intersection25.

Level of Service

General

Various methods may be used to define the Level ofService (LOS) at an intersection. While LOS A* is idealit may not be realistic to design for this condition.LOS B or C* is normally the design condition forisolated rural intersections (posted speed of 80 km/hor greater) and LOS C or D* is normally the designcondition for urban intersections (posted at less than80 km/h) although it is not unusual to have LOS E*under specific circumstances or in congesteddowntown areas. *See tables, page 46.



Notes:1. Table does not apply to left turn clearances.2. Where the approach to the intersection is on a significant grade, the formula to be used should be: y = t+V/(2a+70.6g) where g = %

grade/100 and 70.6 = factor 2 x acceleration of gravity (2x3.6x9.81) in km/h/s.3. Perception + Reaction time = 1.8 seconds for posted speeds of 80km/h and over and 1.0 seconds for <80 km/h.4. 3.0 seconds is the recommended minimum for the amber clearance time; 1.0 seconds is the recommended minimum for All-Red.5 If operating speed deviates significantly from posted speed, the operating speed may be used in the calculation.6. If posted speeds are less than 40 km/h, use 3.0 second amber and 1.0 second all-red.

Table 6 - All Red Clearance Interval Times

Table 5 - Amber Clearance Interval Times



The following are the most commonly used:

LOS Based on Delay

The Level of Service for signalized intersections maybe defined in terms of delay, which is a measure ofdriver discomfort and frustration, fuel consumption,and lost travel time as given in the HCM8. Table 7gives LOS for signalized intersections.

LOS Based on Probability of Clearing the Arrivals

In this (more commonly used) method, LOS is basedon a probability that all vehicles arriving in the criticallane will clear the intersection in one cycle (one greeninterval). This method is based on average lane arrivalsper cycle per critical lane and the actual arrivals couldbe different. The percentage of time that this is achieveddefines the LOS as given in Table 8.

LOS Based on Volume/Capacity (V/C) Ratio

This simple method is based on the calculation of acritical intersection volume. This volume is thencompared to a benchmark intersection capacity fordetermination of LOS. This method does not takeinto account the signal timing or phasing. Table 9gives the capacity ranges of an intersection for eachlevel of service.

Determination of Green Interval Timing

General

The highest rate of traf fic flow begins afterapproximately two to three vehicles per lane havestarted through the green signal because the initialheadway of the vehicles is significantly longer thanthose experienced under saturated traffic flow. Theresult of this is that the first several seconds of thegreen interval accommodates significantly fewervehicles in terms of vehicles per second than the latterportion of the interval.

The analysis of the traffic flow to determine greeninterval times may be accomplished by several methods.Three of the commonly used methods used in Ontarioare as follows:

Ministry of Transportation Methodology

This method uses the Traffic Control Signal Timingand Capacity Analysis at Signalized Intersections(TCSTCA25) manual.

Table 7 - LOS Based on Delay

Source: Highway Capacity Manual 8

Table 8 - LOS Based on Clearing Arrivals

Table 9 - LOS Based on Volume/Capacity



The MTO methodology for calculating green timesemploys the Poisson random probability function.

This is based on the concept that vehicles arriving at asignalized intersection will, to a certain degree ofprobability, be able to clear the intersection duringthe first green interval encountered upon their arrival.The Poisson distribution is used because it has beenfound to give a reasonably good simulation of actualtraffic conditions at signalized intersections.

The level of service is a measure used to describe thequality of traffic flow under various operating andgeometric conditions. The degree of probability ofthe vehicles clearing the intersection determines thelevel of service. There are five levels of servicedescribed in this method, each with a different degreeof probability of clearing the average arrivals duringthe first green interval after arrival at the intersection.

If the total number of vehicles per hour arriving at theintersection is divided by the number of signal cyclesper hour, the average arrival rate (m) is determined.Lookup tables have been developed for both rural andurban commuter environments that show therelationship between average arrivals for each clearanceprobability (level of service) and the time required forsuccessive vehicles to enter the intersection upon thestart of the green interval. For a desired level of serviceand calculated average arrival rate, the correspondinggreen plus amber time can be found in the lookuptable.

The Traffic Control Signal Timing and Capacity Analysisat Signalized Intersections Manual and software(“MTOP”) based upon this method is available fromthe Ministry Of Transportation of Ontario, Traffic Office.

Canadian Capacity Guide Methodology

The Canadian Capacity Guide for SignalizedIntersections, 2nd Edition, (CCG1) gives a theoreticalmethod for determining capacity based on saturationflow. In this method Saturation Flow is defined asthe rate at which vehicles that have been waiting in a

queue during the red interval cross the stop line of asignalized intersection approach lane during the greeninterval. This method generally employs the use ofarrival flows to represent travel demand for theanalysis, design or evaluation at the intersection.

The guide uses lane by lane analytical techniques.The procedure requires all arrival flows and saturationflows to be expressed separately for each lane. Thecritical lane is identified by the highest flow ratio in agiven phase and is computed as the ratio of arrivalflow and saturation flow. The sum of the flow ratiosfor the critical lanes is called the intersection flowratio and provides an indication of the quality ofservice at the intersection.

The allocation of green intervals, that is the duration ofindividual phases, within the cycle time normallyemploys the proportioning of the total available greentime based on the relative values of the critical laneratios for each phase.

Degree of Saturation, Capacity, Probability of DischargeOverload, Queuing and Delay are all measures ofeffectiveness that are used to evaluate how theintersection operates.

The principles employed in the HCM and CCG haveidentical theoretical foundations. The documentsdiffer in the applications of these basic principles, inthe measured values, and in the calibratedrelationships that reflect specific conditions in Canadaand the USA. This edition of the CCG establishes alink between the average overall delay used in the CCGand the average stopped delay applied in the HCM forthe determination of the level of service.

Software based upon this method is available fromprivate sources.



Highway Capacity Manual Methodology

The Highway Capacity Manual (HCM8) method usesvolume to capacity ratios and average delays tomeasure intersection performance. Volume tocapacity ratios provide a measure of sufficiency ofcapacity, and average delays provide a measure ofthe quality of service.

Capacities are determined by multiplying “SaturationFlows” by the proportion of time the movements havegreen during the design hour. Simply stated,saturation flow is the number of vehicles per hourwhich can pass through an intersection via a lane groupunder prevailing traffic and roadway conditions,assuming green 100% of the time. Delay is estimatedbased upon Webster’s delay formula.

This method takes into account operational objectives,and can be used to determine green interval timingbased on balanced delays and/or volume to capacityratios, or maximizing either measure for preferredapproaches.

The Highway Capacity Manual is available from theTransportation Research Board. Software (“HCS”) basedon this method is available from McTrans.

Calculation of Green Extension Time

Where actuation of an individual intersection is used,the green interval timing may be set to a fixed initialportion plus a variable extendible portion whoseduration varies in response to traffic on that phase.The green interval time maybe extended up to a setmaximum value (“Max1”). The minimum time for thegreen interval is the fixed initial portion plus one unitextension of the extendible portion, and is the timerequired to clear stopped vehicles between thedetection and stop line. For practical purposes, theinitial portion may be taken as (detector to stop linedistance as per subsection 5.9) x 0.25 + 4 seconds.

A unit extension may be the time allowed for vehiclesmoving at average speed to travel from the long distancedetectors to within one second travel time from thestopline. In some systems, the unit extension timeshould be based on holding the phase green whiledemand for the conflicting flow is present and loopplacement distance is based on gap timing.

Vehicle actuations during the initial portion have noeffect on interval timing, but each succeeding vehicleactuation during the extendible portion cancels theprevious unit extension and starts a new extensiontiming. This will extend the green interval as long asvehicle actuations are spaced closer than the time seton the extension detector unless terminated by a“maxout”.

Determination of Delays On Actuation

Where actuation of an approach or phase is used, adelay in the registration of a vehicular actuation atthe controller may be set for the detectors. This delayis commonly used for vehicles which stop at thedetection device but which are turning when a gap isavailable in conflicting traffic. The delay time isnormally set from 5 to 12 seconds and if the detectiondevice is not cleared by the vehicle, the controlleractivates the phase change to allow the vehicles toproceed.

Calculation Of Pedestrian Timing

General

Where pedestrians are present at signalizedintersections, the minimum safe crossing needsshould be accommodated in the pedestrian interval(walk) and pedestrian clearance interval (flashing don’twalk) times. The total time of these two intervalsshall be sufficient time for pedestrians to clear theconflict zone prior to the release of a conflicting trafficmovement. Pedestrian timings must be generous



enough to ensure that pedestrians are given enoughtime to cross safely and comfortably, yet not over-generous such that service to vehicular traffic is undulycompromised.

The pedestrian clearance interval, or “Flashing Don’tWalk” (FDW), may include the vehicular amber andall-red clearance intervals. The advantage of includingthe clearance interval times is in giving the pedestriansreassurance that they still have the right to be in theintersection because the method allows the changefrom FDW to solid Don’t Walk to be delayed as longas possible. A disadvantage to this approach is thepotential conflicts between pedestrians still in thecrosswalk and turning vehicles which are trying to clearthe intersection. The FDW should not be less than 5seconds duration except in exceptional circumstancessuch as for crossing a very narrow (two lane) roadwayat low posted speeds. Here, the pedestrian clearanceinterval may be reduced to 3.0 seconds minimumprovided that it terminates upon activation of thevehicular amber interval.

When the vehicle green plus amber and (optionally)all-red clearance times are in total greater than thecalculated minimum total pedestrian Walk andpedestrian clearance intervals, the additional timeshould be added to the Walk time. When the pedestrianWalk plus clearance interval times are greater than therequired vehicle phase time, the pedestrian values shalloverrule the required vehicular values and the vehiclegreen interval shall be extended to at least match thepedestrian total interval times.

The walking speed of pedestrians (Ws) normally varies

between 1.0 m/s and 1.25 m/s. A normal walkingspeed of 1.25 m/s is usually assumed for initialcalculations although the time of 1.0 m/s can be usedat crossings frequented by young children, seniorsand disabled persons. The timing can be fieldadjusted for such conditions, however, on widearterials it is normally the total pedestrian time thatgoverns the time available for other intervals andtherefore the minimum cycle time.

Several methods of timing are available for use.

Method A (TCSTCA25)

In this method, the pedestrian clearance interval shouldallow for pedestrians to at least reach the mid point ofthe roadway. Values of 50% of the pedestrian walkingtime are used for timing of the pedestrian clearanceinterval. The “flashing hand” pedestrian clearanceinterval normally terminates with the beginning of theassociated through traffic amber. For a normal walkingspeed of W

s and a minimum starting time of 5 seconds,

the total pedestrian crossing time is (5+ Wc/W

s)

seconds where Wc is the pedestrian crossing distance

in metres.

The pedestrian crossing distance, Wc, may be taken

as the longest distance within the crosswalk measuredfrom the point of stepping onto the pavement to thepoint of non-conflict with any traffic or the distancefrom curb to curb along the centreline of the crosswalk.

To provide a suitable pedestrian clearance time, apercentage of the total time is used. If, for example,50% of the pedestrian walking time is assigned tothe Walk interval, the flashing “Don’t Walk” intervaltime is also 50%. The philosophy is that pedestriansmust be provided with meaningful indications bykeeping the pedestrian clearance interval as short aspractical while still providing proper crossing andwarning times.

Method B (CCG1)

This method is included in the Canadian CapacityGuide 1. For crosswalks without an island refuge(islands less than 1.5 m width), the pedestrian walkinterval should allow time for the pedestrians to noticethe change of the signal indication, to initiate thecrossing.



The minimum pedestrian walk interval time is typicallytaken as 10 seconds with 7 seconds used as anacceptable minimum.

The pedestrian clearance interval time is Wc/(W

s) in

seconds which allows a pedestrian to walk the fulldistance during the clearance interval.

Method C (Metro Toronto 17).

This method is taken from Metro Transportation’s“Pedestrian Crossing Time at Signalized Intersections17”.This method relies on the termination of the FDWclearance interval at the start of vehicular amber. Thisallows a 5 to 7 second margin of safety for pedestrianswhile the vehicle amber and all-red intervals aredisplayed.

The total pedestrian crossing time is Wc/1.20; of this

time, 5/8 of the total time is allocated to the flashingDon’t Walk clearance interval and the balance isallocated to the Walk interval. Minimum values of 7seconds for Walk and 5 seconds for flashing Don’tWalk are required.

Pedestrian Actuation

When the minimum vehicle green interval is less thanthe minimum pedestrian crossing time plus thepedestrian clearance time (for vehicles at intersectionswith traffic actuated controls), the green vehicle timemay be extended upon pedestrian actuation (normallyby pushbutton) where the equipment allows this typeof programming. An exception to this may occur atrural intersections with very few pedestrians andoperating in semi-actuated mode. In this case,pedestrian pushbuttons may be used, withoutpedestrian signals, to change and extend the normaltraffic signal indication, provided that a signal headexists on the same side of the road facing theactuating pushbutton.

In most operations, the pedestrian pushbutton actuationis accepted as a call during all times except when theWalking Pedestrian indication is underway.

Determination of Cycle Length

Guidelines

The calculation and selection of cycle lengths requiresan estimation of the “lost capacity” per phase due tostartup headways and the effects of cycle length onvehicle delay. It also requires good judgement on thepart of the traffic engineer/analyst.

Guidelines for cycle length selection are as follows23:

• The useful range for cycle lengths is between50 and 120 seconds 25 ;

• For low speed urban roads (10 to 12 m width)and lighter traffic, a cycle length of 50 to 70seconds is preferable;

• Where roadways are wider (over 15 m), withlonger pedestrian walk times (over 20seconds), or where heavier traffic is present orturning interference is significant, a cyclelength of 60 to 90 seconds would berequired to serve minimum timingrequirements;

• Where three or four phases are present, a cyclelength of 90 to 120 seconds is preferred;

• For capacity calculations, a cycle length of 90seconds is usually considered optimum, sincelost time is approaching a minimum, capacityis approaching a maximum and delay is nottoo great;

• Intersection capacity drops substantially whencycle lengths fall below 60 seconds (a greaterpercentage of available time is used by theclearance intervals);



• Impacts of cycle length on pedestrian and sideroad wait times and on side road and left-turnqueue lengths should be considered in theselection of cycle length;

• There are only minimal increases in capacitywhen cycle lengths rise above 100 seconds(as any through green interval approaches 45seconds duration, there is a decrease insaturated flow so that less vehicles per lane persecond traverse the intersection);

• In many situations the walk time (walkinterval plus pedestrian clearance interval)required will be greater than the greeninterval time required for traffic. This isparticularly true for side road timing as thepedestrians must cross the wider main roadand at intersections where it is necessary toadjust walk time for the accommodation ofseniors, younger children and/or disabledpersons. In such cases the pedestrian timingwill overrule the green interval timing and thegreen indication will be on but not efficientlyserving vehicular traffic;

• The cycle times in which the lost times foreach hour are minimized are normally thebest. Since these are the longest cyclelengths which are useful up to the point ofdecreasing intersection throughput, the trafficengineer/analyst can normally start with anassumed cycle length (90 seconds issuggested 25) for further evaluation;

• Analysis and evaluation should consideroptimization of the cycle length (to thenearest second) to obtain minimal delays tovehicles and pedestrians and providesufficient capacity to accommodate thehighest LOS possible.

Cycle Composition

The cycle length calculations require that the followingpoints be considered:

• All amber and all-red clearance times are fixedby the speed of the traffic and the width of theintersection; these should therefore be addedup to give the “intergreen”1 times or the “losttimes”25;

• Where interconnected or central systems areoperating, it is preferable to use a cyclelength which fits in with other intersectionsand allows a progression to be coordinated;

• Examination should be made of hourly, dailyand weekly traffic variations to determinewhen different timing plans are required. It isnot uncommon to use different interval timingand different cycle lengths for the trafficfluctuations at different times;

• The establishment of protected left-turnintervals should be considered and it may notbe possible to include the advance left turnplus the through green times in anyprogression if the opposing green timesuffers.

Many worked examples may be found in the TCSTCA25

and the CCG1

3.7 Signal Spacing

Existing Intersection Analysis

Where the road authority has been forced bycircumstances to install traffic signals in closeproximity to each other, the operation of theseintersections must be coordinated if a semblance ofsmooth traffic flow is to be maintained. Downtownarea gridlock is a familiar phenomenon which trafficengineers/analysts have had to continually deal with.Constant adjustments are necessary in order that controlsystems react to a wide variety of traffic circumstances.Transit bus schedules and roadside bus stops alsocontribute to the problems and must be taken intoaccount. The use of one-way streets alleviate the



situation somewhat as the opposing direction of trafficflow does not have to be accommodated. Left-turnlane storage lengths may be restricted and long left-turning traffic queues may interfere with through trafficlanes. Through traffic with familiar motorists will tendto move to the curb lane.

Where private and commercial entrances are presentbetween intersections, vehicles turning into these fromthe roadway will cause friction or even stoppage oftraffic. Vehicles entering from the side roads, wheregaps allow, will partially fill the approach lanes of thenext intersection. The solution of these problems isnot an easy undertaking. Several suggestions forconsideration are:

• restrict turning vehicles at intersections inpeak traffic hours (requires a bylaw andsignage);

• prohibit trucks in selected hours (requires abylaw and signage);

• restrict use of commercial entrance deliveriesin selected hours (requires a bylaw andsignage);

• install reserved lanes such as HighOccupancy Vehicle (HOV) lanes to enhancetransit bus flow;

• analyze traffic flow supplemented by adetailed field study and produce optimumsignal cycle times which may have sub-plansand which correspond to actual observedconditions;

• introduce fully traffic-responsive controlsystems where practical; and

• consider adjusting offsets to relieve queuedvehicles prior to platoons arriving at theintersection.

New Signalized Intersections

Where a new “interstitial” intersection is planned, thedistance between signalized intersections should bereviewed as follows:

• a coordinated system should be consideredfor local or central system operation whereintersections are less than 1.0 km apart forposted speeds less than 80 km/hand lessthan 1.5 km apart for posted speeds of 80km/h and over;

• given that left turn storage lanes do notusually need to exceed 85 m in length for lowLOS, the minimum distance betweenintersections is approximately 215 m for roadsposted at 60km/h or less and up to 350 mfor roads posted at 80 km/h to allow “back-to-back” left turn lanes and proper tapers butnot considering optimal coordination;

• a distance of 215 m between signalizedintersections will usually be sufficient to allowmotorists to recognize and react to eachdevice but not sufficient to provide goodcoordination;

• intersection spacings less than 415 m orgreater than 625 m may affect progressionefficiency at a posted speed of 50 km/h;

• any new intersection will produce delays totraffic flow. Traffic analysis should considerthat the pattern of deceleration, decreasingheadways, stopping, accelerating, adjustingto increased headways and repeating thispattern at the new intersection may produceunacceptable delays in poorer levels ofservice. The CCG1 gives analysis methods fordetermining whether continuous queues willexist and the delays to be expected;

• the optimal distance for coordination betweensignalized intersections, considering a two-wayarterial only and not considering networkeffects, is, at 50 km/h posted speed:



Cycle length Distance

60s 416 m

70s 486 m

80s 555 m

90s 625 m

3.8 Flashing Operation

Advanced Green Flashing Operation

A circular flashing green indication may be used toprovide discrete time or a separate phase for anapproach at the intersection when protected/permissive green is necessary in a single directiononly. The permitted use of circular flahsing advancedgreen may be terminated in the future. The use ofthe circular flashing advanced green is not promotedas a future standard since Ontario is one of only afew users in North America and it may cause someconfusion to out-of-province motorists.

A flashing green arrow may be used when either aprotected/permissive or a fully protected left-turnphase is necessary, on one or more approaches. It isstrongly recommended that a flashing green arrownot be used in the proximity of intersections withcircular flashing advanced greens since drivers maybe confused by the different methods.

The national standards, as given in the TAC MUTCD12,use flashing arrow signals only and do not recognizesteady arrow or flashing circular displays. The use ofthe arrow flashing advanced green is not promotedat this time due to possible confusion of motoristswith Ontario’s circular flashing advanced green. It isrecommended that, if the flashing advanced greenarrow is used, that it only be used in an area whichdoes not have any circular flashing advance greens.In areas where circular flashing advanced greens arepredominant, it is suggested that a program beundertaken to firstly reconstruct these to steady arrowcontrol and then a separate program be undertaken

to convert the arrows to flashing advanced green arrowsat a later date.

The flashing green traffic control signal indication shallbe at a rate of not more than 180 or not less than 150ON and OFF flashes per minute, with the length ofeach ON period approximately equal to the length ofeach OFF period.

Standardized Flashing Operation

Traffic control signals (which do not use left-turn arrowheads, excluding types 8, 8A, 9 and 9A in Figure 1,Section 2), may be switched from their normal phaseindication to flashing operation. Three modes offlashing operation are normally used:

• start-up flash - the signals are commonlystarted with flashing ambers on the mainroad and flashing reds on the side roads;

• emergency flash - when a conflict is detected,the signals are commonly flashed in an all-redor “red-red” mode if the controller flashers havethat capability. The red-red mode has a safetyadvantage over the red-amber mode (reds onside road; ambers on main roads) but the red-amber mode is an acceptable alternative and isconsidered safer on roads with posted speedsof 80 km/h and above and with light sideroad traffic since fewer stops are required ;

• timed flash - the signals may be programmedto operate in the red-red or red-amber modeduring various periods of the night or of theweek or for special events.

Caution should be used in the choice of locations forplanned timed flashing operation of signals. Flashingoperation may be of some advantage to traffic flow,particularly with pretimed signals, when conditionsof very light traffic occur such as during the nighthours, on a Sunday or holiday in an industrial area. Asa guideline, the red-red mode of flashing operation ispreferred for safety over the red-amber mode wheretraffic is heavy and where hardware allows this



allows a limited operation where one or more phasesremain on red and one or more phases remain on greenduring the preemption operation The preemption maybe activated by the following incidents:

• an approaching train on a level crossing whichcrosses one or two of the roadways near orwithin an intersection and sends a signal to theintersection controller upon train approach;

• an approaching emergency vehicle (fire,ambulance, police, etc.) which requires thesignal on the approach to return to green assoon as possible and/or right-of-way to beheld in green on the vehicle approach or onone roadway.

Preemption For Railway Crossings

Where a proposed traffic control signal installation isin close proximity to a railway crossing, the trafficcontrol signal installation should be discussed withthe appropriate railway authority.

Where the railway crossing actually lies within theintersection itself, special treatment of railway andhighway signals will be required to provide greaterprotection for vehicles. Examples of this are given inthe TAC MUTCD12.

In the case of railway preemption, it is extremelyimportant that a preemption sequence compatiblewith the railway crossing signals provide safety forvehicle, pedestrian and train movements. Becausetrains cannot stop in time to accommodate traffic atthe level crossing, it is essential to ensure that theseparate intersection and railway signal devicescomplement rather than conflict with each other18.

The following situations may require railwaypreemption phases and the interconnection of railwayand vehicle signals will then be required:

alternative. The amber-red mode should be used whereside road traffic is very light and where higher speedson the main road may make a red less safe than anamber. A nighttime flashing mode is not necessary atactuated signals since the signal normally rests in greenon the main road and will only change if there isactuation or a pedestrian call from the side road.

It is recommended that the timed flashing mode ofoperation in off-peak hours should not be consideredat intersections with channelizing islands, atintersections with nighttime volumes of trafficexceeding LOS B on the side road, at intersectionswith a proven collision history if hardware of thesystem will not allow red-red flash or at intersectionswith pedestrian crossing required.

In the flashing mode, either the red indication facingall approaches must flash (desirable for safety on busyroads) or the amber flashing indication must face theapproaches on the main road and the red flashingindication must face the approaches on the side road.

The standard flashing red or flashing amber trafficcontrol signal indication shall be at a rate of not morethan 60 or not less than 50 ON and OFF flashes perminute, with the length of each ON periodapproximately equal to the length of each OFF period.The flash rate is slower than that used for flashingadvance green indications.

3.9 Preemption

General

All modern controllers offer two preemption modesof operation in addition to the signal plans provided.The preemption plans available normally include theuse of two railway plans, two to four emergencyvehicle plans or one of each. The preemption mode



1. Where a railway crossing is in proximity to anintersection such that vehicle back-ups in thequeue approaching the intersection, aftercrossing the tracks, may cause an inadvertentvehicular stoppage on the level crossing, itwill be necessary to provide an intersectionclearing preemption phase to allow the trafficto clear the approach prior to train arrival.This situation requires analysis of themaximum traffic flow that can be expectedon the approach and the time required toclear the tracks during the preemption phase(plus a suitable factor of safety).

2. Similarly, a railway crossing may be in closeproximity to the intersection and theactivation of the railway crossing controlgates may cause some panic stopping fromthe intersection side of the crossing and leadto the plugging of the distance between theintersection and the railway tracks. Here, it isnecessary to clear the approach between theintersection and the tracks for the otherdirection of traffic as for case 1, and alsodesirable to prevent the filling of the spacebetween the intersection and the tracks suchthat the intersection does not becomeblocked;

3. Where a railway crossing may be in closeproximity to the intersection, it is alsonecessary to disallow turns into the roadwaywith the railway crossing while the crossing isactive. This may be accomplished either bythe use of arrow signal heads or blank-outsigns or a combination of both.

A recommended practice of the Institute ofTransportation Engineers titled “Preemption of TrafficSignals At or Near Railroad Grade Crossings withActive Warning Devices”18 gives recommendations onwhen to preempt , design considerations andoperations and should be followed when the givenconditions occur.

Signals which require railway interconnection shouldnot be constructed until the approval of the appropriaterailway authority has been received.

Preemption For Emergency Vehicles

Preemption for emergency vehicles can be activatedby a stroboscopic light emitting device or radiofrequency device mounted on the emergency vehicles.The light signal is received by a photosensitive detectorof the proper frequency mounted at the intersectionin the direction facing the approach which will receivethe preempt green indication.

Preemption can similarly be activated by simpledevices such as a pushbutton inside the fire station.These are used locally and normally allow trafficcontrol signals at the fire station entrance to remainon green until the emergency vehicles have left andto activate special preemption phases which alloweasier passage through nearby intersections. Theactivation is similar to the action of a detector sensoramplifier and puts in a call for the preemption phaseto begin after suitable minimum interval times andclearance times have been met. In the case ofcentralized systems, once the initial call is made, amoving window form of preemption can beimplemented.

The optical preemption system normally requires astudy of the arterials to be covered, the types ofvehicles to be fitted and coordination and agreementof cost sharing for the participating parties.



3.10 Operation Of MiscellaneousSignals

Pedestrian Signals

Traffic control systems may be installed at desirablepedestrian crossing locations. The locations may beat intersections (Intersection Pedestrian Signals or IPS)or between intersections (Midblock Pedestrian Signalsor MPS). Both types require that main road traffic befully signalized.

For IPS, the side road must be provided with stop signsif not already provided.

The control of the pedestrian signals is by pedestrianactuated two phase operation with the only phaseindications present being the pedestrian signals acrossthe main roadway and the traffic control signals onboth main roadway approaches.

Pedestrian timing should be set as for normalintersections considering the factors of subsection3.5. The controller should rest in main road greenuntil a pedestrian actuation is received. The controllermay operate in conjunction with the background cycleimposed by a system if required for safety or capacityreasons. Alternatively the controller should have a longminimum green interval programmed for the main roadso that continual pedestrian interruptions of traffic aretolerable.

Transit Priority Signals

A transit priority signal display may be used to assignright-of-way to public transit vehicles over all othervehicular and pedestrian traffic movements within anintersection. The signal indication allows for themovement of transit vehicles through a signalizedintersection. The transit priority signal is generally usedat an intersection and may be operated exclusivelyduring a protected transit movement or concurrentlywith other non-conflicting vehicular movements.

Transit priority signals can beused on either the primary orsecondary traffic signal heads oron both depending on the transitmovement, location of transitlane and operation of theintersection.

Transit vehicles facing a normalred indication and an illuminatedwhite transit vehicle indicationmay proceed through theintersection while all othervehicles and pedestrians muststop and are not allowed toproceed.

Following termination of the transit phase, a normalred clearance interval is required before the signalsrevert to the normal phasing. The transit priority signalmay also be operated concurrently with other non-conflicting vehicular and pedestrian movements asdirected by the traffic control signal indications. Whenthe vertical white bar is not displayed, transit vehiclesmust obey the normal traffic signals. The use of thetransit signals may be required at only certain times ofthe day or on certain days or for special events and theadditional phase(s) can therefore be programmed intoa signal plan.

Movable Span Bridge Traffic Control Signals

When a roadway crosses a drawbridge, swing bridgeor lift bridge, normal traffic signal heads should beconsidered in conjunction with control gates or otherforms of physical protection. The traffic signals andprotection system are to be interconnected with thebridge mechanism in such a way that the signalindications will not change to amber less than 15seconds before the gates are closed and theindications will not show green at any time when thebridge is not traversable. The all red interval shouldallow sufficient time for all traffic to clear the bridgedeck prior to activating the protection devices followed



by the bridge mechanism. In cases where areas oftraffic congestion such as nearby intersections or railwaycrossings are present, traffic presence detection on thebridge may be required to detect any vehicles strandedon the bridge. Where railway crossings are present,another set of advance signals may be required to ensurethat vehicles are not trapped and forced to stopbetween the bridge barrier and the railway tracks. Wheresignalized intersections are within 150 m of the bridgesignals, they are to be interconnected with the bridgesignals and enter pre-emption mode, resting in red inthe direction approaching the bridge, upon activationof the bridge signals by the bridge mechanism.

A great deal of care should be taken with the design ofbridge signals as it is not possible to stop large watervessels in a short distance and, once activated, thebridge mechanism has to continue to open the bridge.It is good practice to allow a significant distance or 15m minimum between the end of the movable part ofthe bridge and any barrier protection as a place to parkone or two vehicles in an emergency.

Lane Direction Signals

Lane direction signals are used to legally indicate thedirection of traffic flow on reversible direction lanes.The downward green arrow indicates right-of-way inthe lane for through traffic approaching the display.A red “X” indicates that approaching traffic must nottravel in the lane. A separate display must be usedover each reversible lane and the heads are normallymounted back-to-back if visibility from both directionspermits.

Lane direction signals may be used in conjunction withcontrol gates to physically indicate closure of lanes orroads.

Amber “X” indications are not used for clearanceintervals in Ontario. A flashing red “ X” can however beused as a clearance interval. Where hardware doesnot allow for a flashing red “X” clearance of the timerequired, it will be necessary to allow enough phasetime to allow a vehicle travelling at normal speed tocompletely clear the full length of the lane (by use ofa long all red clearance interval) prior to switching tothe reverse direction. Alternatives to this methodinvolve vehicle detection and axle counting as well ascontroller software modifications to allow reversal onlane clearance.

Portable Lane Control Signal Systems

Portable Lane Control signal systems consist of asingle “standard” vehicle traffic signal head, normallymounted on a movable pole. These signals aresometimes used to reduce traffic flow to a single lanein alternate directions at very local work areas on theroadway which requires lane closure. The phasingintervals must be for a two phase operation only, withthe all red clearance interval sufficiently long to clearthe previous approach lane of all vehicular traffic whiletravelling at the desired operating speed.

Communications between the signals at each endmust be provided in order to prevent conflictingdisplays.

Audible Indications

Audible indications consist of audible semiconductordevices which emit “peep-peep” and “cuckoo” signalswhen walking pedestrian symbols are operational.Actuation of the pedestrian signals is recommendedto be by an oversized pushbutton. The audible signalsare crosswalk specific, normally applied at least acrossthe main road.



Audible indications are not covered by the HTA.Standards and pushbutton operation options areprovided in the TAC MUTCD12.

Tunnel Signals

“Tunnel Signals” are composed of two types:

• signals at the ends of a tunnel which are usedto prohibit the entrance of traffic in the case ofa mishap within the tunnel;

• lane control signals within the tunnel, and onthe tunnel approaches, used for reversiblelanes or for the closure of lanes formaintenance.

Signals located near the ends of a tunnel areconstructed at crossing roads, if possible, in order thattraffic may be diverted should it be necessary to closethe tunnel. The tunnel may be closed by a manuallyactivated or automatic preemption signal to the signalcontroller from the tunnel alarm systems for fire,collision, noxious gases or heavy water leakage. Thesignals operate similar to those for railway preemption,with arrow control and/or blank-out signs.

Lane direction signals within a tunnel are sometimesrestricted in size due to vertical clearance. The principlesof visibility outlined under “Lane Direction Signals”elsewhere in this section should apply.

Ramp Metering Signals

Ramp metering signals are used on freeway orexpressway entrance ramps to control the rate ofvehicle entrance to the highway. The operation ofthe metering signals is normally carried out only duringrush hours and in a preferred direction (normallytoward the CBD in morning and outbound from it inthe evening).

The ramp metering signals are normally controlled bythe traffic management computer software from theTraffic Operations Centre. The signals have acontrolled cycle length which is dependent on the

volume/density of the highway lanes. When thehighway is operating at LOS E, the ramp metering cyclelength will be relatively long (e.g. 15 seconds) suchthat the number of vehicles per hour is restricted inorder to alleviate the highway congestion. When thehighway speeds increase and volumes of throughputincrease, the central computer commands a relaxationin the ramp metering cycle (e.g. 5 seconds) thusallowing more vehicles per hour from the ramp to enterthe highway.

The ramp metering station (RMS) itself requires acontroller with modified software/firmware to accessvalues of minium green and amber which are normallydisallowed for intersection controllers. The greeninterval time is normally set to a very short one in theorder of 1.0 seconds (one vehicle only per greensignal) with the amber even faster and in the order of0.5 seconds. The signals rest in red for the remainderof the cycle and must be activated by a detector whenthe system is running. In off-hours of the day, thesystem is not operating and in this case, the signalsrest in green.

Ramp metering signals are always used in conjunctionwith an advance flasher to indicate that RMS is inoperation.

3.11 Flashing Beacon Signals

General

Flashing beacons may be used at locations wherefull traffic control signals are not justified but where,due to lack of visibility or other hazards, regulatory orcautionary signs are not sufficient. Either flashingred or flashing amber indications may be shown, thered indicating that all approaching traffic must stopbefore proceeding and the amber indicating thattraffic may proceed with caution provided that theway is clear. The red flashing beacon is always usedin conjunction with a stop sign.



Beacons shall be clearly visible to approachingmotorists for the distances shown in Section 5.

Beacons shall be flashed at a rate of not more than 60nor less than 50 ON and OFF flashes per minute, withthe length of each ON period approximately equal tothe length of each OFF period.

Beacons should be used with considerable discretionbecause over-use of these devices has led to theirdisregard by motorists.

Hazard Identification Beacons

Hazard beacons include those used for reinforcementof signs for obstructions in or immediately adjacentto the roadway, supplemental to advance warningsigns and supplementary to regulatory signs such asSTOP, YIELD and DO NOT ENTER. They are also usedas visual warning on pedestrian crossovers.

Beacons with flashing amber indications may be usedto emphasize the need for caution when studies indicatea problem is present at the intersection (e.g at least sixcollisions over the previous 36 months have occurred)and where one of the following conditions exist:

• a physical obstruction in the roadway;

• a sharp curve in the roadway;

• a major intersection is hidden by a sharpcurve or severe grade.

Beacons in Advance of A Signalized Intersection

An amber keep right flasher on a median island shallbe used only if it does not visually distract from theintersection signal ahead and this type of flasher istherefore seldom used. The flasher should not beused where it will be a visual distraction to a signalizedintersection, midblock pedestrian signal, pedestriancrossover or where it will cause possible confusion(generally a minimum of 300 m away).

Intersection Control Beacons

General

An intersection control beacon consists of one or morehead sections with either 20 cm or 30 cm diameterlenses with continuously flashing red or amberindications. Applications include overhead beaconsmounted on suspension wire at the centre of anintersection and visual assistance where stop signsare not conspicuous.

Flashing beacons may be used when two major highspeed roads intersect in a rural area or when anaverage of three reportable personal or propertydamage collisions per year for at least three yearshave occurred and were directly attributable to poorobservance of the STOP sign.

1-Way or 2-Way Overhead Red Flashing Beacons

These types of beacons are used where the visibility ofintersections or stop signs is poor due to abrupt verticalcurves or other visibility restrictions. The applicationis used basically to provide visual assistance to normalstop signs and require 24 hours a day operation.

These types of overhead beacons should use 30 cmred lenses and be positioned to aim along eachapproach of the side road. Normal stop signs arealso located on the side road approaches as backupin case of beacon failure.

3-Way and 4-Way Overhead Red Flashing Beacons

These types of beacon are used where ”all-way” stopconditions are in place but traffic control signals arenot justified. The beacons are used in conjunctionwith traffic, geometric or visibility conditions thatrequire reinforcement of the normal usage of stopsigns. The beacons require 24 hours a day operation.

These types of overhead beacons should be positionedto aim along the approach of each road. Normal stopsigns are always required on each road approach.



3-Way and 4-Way Overhead Red/Amber FlashingBeacons

These types of beacons are used where stop conditionsare required on the side roads and caution conditionsare required on the main road but traffic control signalsare not justified. The beacons are used in conjunctionwith traffic, geometric or visibility conditions thatrequire reinforcement of the normal usage of stop signsand where side road traffic has some problems infinding an acceptable gap for turning or have limitedvisibility.

These types of overhead beacons should be positionedto aim along each approach road of the intersectionwith the red beacons facing the side road(s) and theamber beacons facing the main road. The beaconsrequire 24 hours a day operation. Oversized stop signsare also located on the side road approaches.

Red Beacon For Stop Sign Reinforcement

This type of beacon is normally used above an oversizedstop sign on long flat approaches to intersections thatexhibit poor visibility of the intersection due to fences,tall weeds, etc. and do not justify traffic control signals.The beacons should be 20 cm diameter to preventexcessive glare caused by the low mounting height.The beacons require 24 hours a day operation.

Warning Beacons at Signalized Intersections

Continuous Advance Warning Beacons for TrafficSignals

These types of single 20 cm diameter beacons areused as a reinforcement to the “Signals Ahead”symbolized warning signs where visibility ofintersections with traffic control signals is restricted,where signal observance is found to be substandardor where signals may not be expected by motoristssuch as on remote highways.

The beacons may be used with horizontal roadwaycurvatures which are made visually abrupt by buildings,rock cuts or large signs along the inside of curves oron abrupt vertical curves in locations where the trafficsignal indications are not visible from the minimumdistances from the stop lines as given in Section 5. Inthese situations, continuous single flashing beaconswith the oversized “Signals Ahead” sign (Wb-1102A)may be required. The location of the signs are notcritical and can be located at any reasonable distanceupstream from the signalized intersection, beyond thedistances shown in Section 5, in general conformancewith the requirements shown elsewhere in the OntarioTraffic Manual - Warning Signs, and in a location thatprohibits view of both the beacon and the intersection.

Active Advance Warning Beacons for Traffic Signals

These types of double 20 cm diameter beacons maybe used as a reinforcement to the “Signals Ahead”



symbolized warning signs where visibility ofintersections with traffic control signals is restrictedby geometric and physical constraints and wherestudies indicate that traffic speeds, visibility, volumesand collision rates or collision severity are problems.For example, these types of beacons are used attemporary signalized intersections on freeways andare of the active type because stopping is not normallyrequired and hence the continuous type of beacon isundesirable. The beacons are normally employed toaid motorists in defining the edge of the dilemma zoneand indicating that there is a good probability thatstopping is required.

Visibility problems may be particularly bad where treesenter into the sight lines and opposing vehicleheadlights produce high glare at night. Other usesinclude warning of signals at the bottom of a longsteep downgrade, where an intersection is not visibleto approaching traffic, where a traffic control signal isunexpected such as on a divided highway and at theend of a long length of road where no signals havebeen seen for a substantial length of time.

Active 20 cm amber double flashing beacons(“bouncing ball” effect) with the oversized “SignalsAhead” signs (Wb-1102A) and complete with the wordtabs “PREPARE TO STOP WHEN FLASHING” (Wb-102At) may be required.

The beacons should be connected to the intersectiontraffic signal controllers to give advance warning ofupcoming amber indications or to at least indicatethe start of amber for actuated signals. The beaconsbegin to flash as the signal changes from green toamber, or a set time in advance of the signal changingfrom green to amber to provide additional warning.

The flashers can be connected as a separate phasewhich starts early and finishes late. Conversely, the170 controller program #233 is equipped to handlethe flasher operation as are some NEMA controllersif they are provided with an “advanced warningpackage”.

Vehicles passing the signs when the beacons are notflashing must have sufficient green time when thebeacons are activated before amber, or sufficientclearance time if the beacons are activated when theamber comes on, to clear the intersection. Site conditionjudgement on the part of the engineer/analyst isrequired to determine the correct timing of the flashers.

The beacons and signs should be accurately locatedsuch that vehicles passing the signs and beacons whenthey are flashing have sufficient time and distance tostop before the intersection.

If the beacons are set to come on a fixed number ofseconds before amber, most controllers will give afinal extension to the green after gap-out or max-out.With this operation, the signs should be placed at adistance of (operating speed (m/s)x amber time +added extension time) from the stop line. If beaconsare set to come on with the amber, the sign should beplaced at (operating speed (m/s) x amber time) fromthe stop line.

3.12 Systems

Need for a System

The need for a traffic signal control system isdependent on the levels of efficient traffic flow throughthe various intersections being considered. Somegeneral guidelines to be considered are:



• spacing of intersections along an arterial orwithin a grid;

• the number of locations approaching LOS Ewhich could not operate within a commonbackground cycle length;

• two or more parallel arterials experiencingsimilar problems;

• impending occurrences of “gridlock” oncrossing arterials;

• demographics of the signals; outlyingsuburban signals will operate entirelyseparately from those of the downtown corefor example;

• the LOS expected locally; motorists in densedowntown environments of large cities maytolerate more congestion than those insmaller communities because they are usedto it;

• number of signals in the municipality; up to64 sets of signals on two or three arterialscan be controlled with an interconnectedsystem using a system master controller atthe main or critical intersection;

• over approximately 75 signals requires fulltime traffic attention and use of a centralsystem not only enhances the managementof the signals at the intersections but allowsobservation and analysis from a centrallocation.

Types of Systems

General

The types of systems to be used should bear in mindthe functionality expected in the area to be served.Many municipalities have several independent systemsoperating and outlying areas are only brought intothe central main system after the areas have beenbuilt up. The following are guidelines which may beconsidered in a study of the systems to be used:

Arterial Interconnected System

The arterial interconnected system or the “distributedclosed loop arterial system” uses a field arterial systemmaster controller connected to a series of slavecontrollers. Interconnection of up to 64 intersectionsmay be accomplished by the use of a communicationssystem. The methods of interconnection are basedon the master controller containing the programmingfor the system. The local or slave controllers along thearterial, or crossing arterials, follow the command ofthe master for which control plan to use. The masterhas the ability to select a traffic plan or cycle lengthin each controller on the system in order to optimizetraffic flow.

Input parameters may be entered locally or viatelephone or other communications modes from acentral PC. The master normally sends a commandto synchronize the slave controllers at time zero. Eachslave has a local offset for its cycle to start and tochange the time-of-day plans of the controllers.Several types of interconnection are available:

• “hard wired” interconnection using oldertechnologies such as 7-conductor trafficsignal cable operating at 120 Volts or “tonecontrol” or modem interconnection usingextra-low voltage cable operating at 24 Volts;

• “wireless” systems which use modulated RFradio type emissions to transmit and receivethe coordinating signals or “time based”interconnection where each controller isprecision timed using a digital time clock tofollow the master at predetermined times ofday.

Further information should be obtained from thecontroller manufacturers since each method has itsown advantages and associated costs.



Grid Interconnected System

Interconnection of up to 255 sets of signals may beaccomplished by the use of one of the interconnectionmethods. Typically the critical intersection controlleris set as the system master and coordination of plansand offsets is calculated to achieve optimal traffic flowalong arterials in both directions. This system worksbest where the directions of heavy traffic during aparticular time of the day are easily determined andintersection spacing is regular and fits a good cyclelength.

Small Central System

A small central system or “centrally distributed” systemmay be operated from a PC with software suppliedby the controller manufacturers. Typically, the centralcomputer addresses a field zone master controller ona dial-up basis. The zone master then controls itsown slave controllers. The slave controllers can alsobe accessed directly in some systems. The systemsare sold on the premise that up to 5760 signals maybe controlled but the practical limit appears to bemuch less.

In these systems, each arterial is coordinated in apreferred direction for any time-of-day or trafficresponsive plan to approximate efficient traffic flow.Limits on the software application do not allow formore than 32 plans to effectively be used.

Several manufacturers offer small central systemsnamed as Management Information Systems forTraffic. System operating software packages usedatabases and other software devices to enablereporting of many traffic flow functions and are a goodaid to analysis where traffic problems are occurring.

The packaged programs available are normallyoperated on a state-of-the-art PC or miniframe, are animprovement over most of the older central distributedsystems and allow the user to select the customfeatures to be analyzed and reported.

Large Central System

A large central system or “mainframe” system maybe operated within a large city or region withcustomized software allowing multiple time-of-dayplans or traffic responsive plans. Time of day plansare generally used but “system loops” may be installedin bellwether locations on inbound and outboundarterials and the system plan may be chosen by thesoftware to correspond to the reported traffic densityand volumes. More commonly, software plans areset to multiple time of day plans which are derivedfrom field studies, observations and experience forvarious times of the year.

Traffic Adaptive System

Software programs such as the “Split Cycle OffsetOptimization Technique” (SCOOT) have been installedin Metropolitan Toronto. These types of programs relyon loops in each lane installed upstream of allintersections. Detectors measure traffic density andthe central computer calculates the optimal splits andoffsets of the signal set ahead so that the trafficplatoon will theoretically move through the next andsucceeding intersections smoothly. Optimal cyclelengths are also calculated for user-defined controlareas (such as major arterials) and these assist inoptimizing traffic operations according to user-definedparameters. The costs of installing, calibrating andmaintaining detection equipment for such a systemis significant, but improvements to traffic operationsand reductions to delay can be significant, particularlywhere traffic flow patterns change frequently.



4. Planning and Justification

4.1 General

Purpose

This section addresses the justification or needs fortraffic control signals. A comprehensive study of thetraffic conditions and the physical characteristics ofan intersection or mid-block location should beundertaken in order to determine whether or not theinstallation of a traffic signal is justified.

Background/Context

In Ontario, traffic signal installations were, until the1990s, subject to cost-sharing between the Provinceand the municipality within which they were located(except for signals on provincial highways, which werefully a provincial responsibility). The Province, byapplying a standard set of “warrants”, ensured thatonly signal installations that met these warrants andthe design requirements in the HTA were eligible forprovincial funding subsidy. Municipalities were freeto install signals at other locations at 100% municipalcost, but meeting provincial warrants became a keyfactor in prioritizing signal installations.

The warrants were derived from U.S. practice andstandards developed during the 1920s and 1930s andupdated periodically. Canadian practice was guidedby the Canadian Manual of Uniform Traffic ControlDevices which, until its revision in 1974, followedclosely the U.S. equivalent. The revised CanadianMUTCD12, produced by the Transportation Associationof Canada, used an entirely different points-basedapproach and has subsequently been adopted byseveral provinces. Ontario has maintained its ownMUTCD in the style of the U.S. warrants system.

In order to ensure that the warrants then used wereup-to-date and accurate, the Ministry of Transportationof Ontario convened a Committee in 1978 comprisingfive municipalities and itself. The Committeerecommended that the warrants be updated in fourmain ways:

• changing the eight hour volume warrant frombeing met on average to being met duringeach of the eight highest hours;

• the free flow/restricted flow “break point”was revised from 60 km/h to 70 km/h;

• the cross traffic definition was made morespecific; and

• the warrant for “T” intersection minor streetvolume was increased by 50%.

After a period of provincial and municipal review, therevised warrants came into effect on January 1, 1982and were published as part of the Ontario Manual ofUniform Traffic Control Devices.

Current Update

The update contained here (2000) follows the sameapproach as in 1978, with a Committee of experiencedmunicipal and provincial practitioners being formedto review current practice and suggest improvements.

The most significant results of the 2000 update are:

• confirmation of Ontario warrants anddecision to not include one hour and fourhour volume justifications for signalinstallation at this time;

• expansion and clarification of justificationused for pedestrian signals;

• revision of the supporting text to be moreaccessible and provide additional context;and



Table 10 - Information to be collected

* In addition to items 1, 2, 4, 5, 8, and 9, Justifications 1 and 2 must be calculated as part of Justification 4.

** Justifications 1, 2 and 3 must be calculated as part of Justification 5.



• adaptation of criteria to a computerspreadsheet format.

With respect to the last point, fitted equations havebeen provided for all graphics.

Although one hour and four hour warrants are includedin the current U.S. MUTCD11, the Committee did notsupport the inclusion of either concept in the OntarioTraffic Manual at this time. Also, a brief review of thebasic volumes used in justifications 1, 2 and 3 did notreveal that any significant changes were needed. It isrecognized, however, that further research would beuseful to definitively address the issue of whether thevolumes and their underlying assumptions regardingvehicle characteristics and motorist behaviour accuratelyreflect today’s rural and urban operating conditions.In that respect, it must be continually emphasized thatthe justification values cited herein are only standardtechnical measures which do not necessarily addressall situations and which must be used in conjunctionwith experienced engineering judgement reflective ofthe community needs, financial resources, networkimplications, traffic patterns, and physical conditionspresent.

4.2 Information Requirements

Basic Input Data

The information indicated in Table 10 should becollected for use in the analysis of signal justification.Note that not all information items need be collected,only those relevant to the likely justification to beapplied (e.g. there is no need to gather pedestriandata at a high-volume intersection for whichJustifications 1 and 2 will govern). The collectedinformation may be summarized in the form of Table10 for ease of reference.

Supplementary Input Data

The quantitative Justifications 1 - 5 are, as notedearlier, to be applied in conjunction with engineering

judgement and within a qualitative context. Thefollowing data may provide a more preciseunderstanding of the operation of the intersection andassist the analyst in applying additional engineeringjudgement to the results of the signal justificationanalysis. Such information may be obtained duringthe time periods for which the relevant Justificationapplies:

1. Vehicle DelayVehicle-seconds delay determined separatelyfor each approach.

2. Gaps (Unsignalized Intersections Only)The number, length, and distribution of gapsin vehicular traffic on the main road whenside road traffic experiences significantdelays.

3. Site ConditionsA condition diagram showing the intersectiongeometrics, lane arrangements,channelization, pavement markings,pedestrian paths, sight distance restrictions anddistance to nearest traffic signals. Tosupplement the above basic data, the conditiondiagram may also include approach grades, busstops and routing, on-street parking conditions,driveways, streetlighting, utility poles andfixtures and adjacent land use / plans.

4. Future DemandIf significant changes in traffic volume orintersection layout are anticipated in the nearterm, these should be quantified. Specificallythe Design Hourly Volume (DHV), AverageAnnual Daily Traffic (AADT), or AM or PMpeak hour volume for the construction year isneeded as a basis for calculating futurewarrants. This future volume may reflect sidestreet traffic attracted to the new traffic signalupon a significant reduction in delay.



Table 11 - Basic Input Data

4.3 Principles of Justification

General

The initiative to consider installing a traffic signal atan existing intersection or mid-block location willgenerally arise from complaints or analysis regardingdelay, congestion, safety, or pedestrian crossingproblems. The resultant investigation of the need fora traffic control signal shall begin with the collectionof traffic, pedestrian, collision and geometric data (asdescribed in section 4.2). Then, an assessment ofwhether or not a signal is technically justified is made,using the following criteria:

Justification 1 - Minimum Vehicle VolumesJustification 2 - Delay to Cross TrafficJustification 3 - Collision ExperienceJustification 4 - Combination JustificationJustification 5 - Pedestrian Volume

For a traffic control signal installation to betechnically justified at least one of the abovejustifications shall be fulfilled. Unless one or moreof the signal justifications are met, the installation ofsignals would not normally proceed as it would likelyresult in an increase in overall intersection delay and/or a negative impact on intersection safety.

Guidelines and Exceptions

Justifications should be used as a guide to determiningthe need for traffic control signals rather than asabsolute criteria. The fulfilment of a traffic signaljustification or justifications shall not in itself requirethe installation of a traf fic control signal; thejustifications must be used in combination withexperience, professional judgement and economicanalysis. The satisfaction of the signal installationjustifications is only one criterion for determining thesuitability of traffic control signals for any location.

Hour Hour

EndingEnding

8th 8th Totalotal

Main RoadMain RoadSide RoadSide Road

Approach 3Approach 3 Approach 4Approach 4 Approach 1Approach 1 Approach 2Approach 2 Pedestredestrian ian CrossingCrossing

Cross Cross Traffic*affic*

Side RoadSide Road

Avererage age Approach SpeedApproach Speed

85th percentile if uncontrolled(km/h)

Main RoadMain Road

LT T

(vph)

TH TH

(vph)

RT

(vph)

LT T

(vph)

TH TH

(vph)

RT

(vph)

LT T

(vph)

TH TH

(vph)

RT

(vph)

LT T

(vph)

TH TH

(vph)

RT

(vph)Vol.ol.

(pph)

DelaDelay y

> 10**> 10**

(pph)

Totalotal

(vph)

Totalotal

(vph)



The decision to proceed with a justified signalinstallation should also reflect a benefit/cost analysisin which the economic benefits are shown tooutweigh the costs associated with the signal and itsoperation (including its effect on delay and collisionrates). The Canadian Capacity Guide1 gives someguidance on evaluation of benefits, and other sectionsof this Manual deal with the costs of collisions.

Even if the intersection situation meets a Justification,a traffic control signal should not be installed if it willresult in operational problems which create a potentialfor collisions and / or significantly increase delays toall users. Potential problems include extension ofvehicle queues through upstream intersections, or abreak in progression in both directions for a highthrough volume. Operation of one-way streetspresents another set of issues which requireengineering judgement to be applied over and abovestrict reliance on the justification criteria.

Underlying all of the justification is the assumptionthat adequate visibility up and downstream is availablefrom a stopped vehicle on the cross street. If visibilityis inadequate for the safe and efficient operation ofthe intersection in its unsignalized form, and geometricor operational improvements cannot resolve thesituation, experience and professional judgement maysupport signal installation even if Justifications 1 -5are not met.

At intersections where transit use is a significantconcern, the disproportionate person-hours of delayexperienced by bus passengers may be consideredby the experienced analyst into the justification.

Definitions

Main road:

The main road should be taken as the road carryingthe greatest hourly vehicular traffic volume over theperiod of study. The “main road”, however, may notcarry the greater volume during each of the hours

studied; refinement of the definition to incorporateanalysis on an hour-by-hour basis is possible. Wherethe intersecting volumes are approximately equal, theroad having the least restrictive form of existing controlis selected as the main road.

Average Day:

The traffic volumes used in the analysis should berepresentative of those likely to be experienced on anaverage day which reflects the problem that the signalis intended to address. Where days during whichsignal justifications are met occur on other thanweekdays (e.g. a busy retail oriented street which iscongested on Saturdays rather than during weekdays,or roads in recreational areas that experience peaktraffic conditions only during summer weekends),signals may be justified on the basis of recurringcongestion but their design and operation shouldreflect the variations in their use. They should beoperated so as not to cause undue delay during themajority of the days during which the demand isreduced.

Within the day, the hours counted should reflect thevolumes experienced during the hours at issue. Trafficvolumes normally vary hourly, daily, monthly,seasonally and annually. If available counts are forthe periods other than the one(s) of interest, they maybe factored appropriately with reference to local orprovincial experience.

Flow Conditions:

The justifications for traf fic signals have beendeveloped for “Restricted” and “Free Flow” conditions.This division is necessary due to the different operatingcharacteristics which exist under each condition.

Restricted Flow (Urban) Conditions are those whichare normally encountered in urban areas where thetraffic volumes approach or exceed the practicalworking capacity of the roadway and operating speedsare generally less than 70 km/h.



Free Flow (Rural) Conditions are those which arenormally encountered in rural areas and incommunities of less than 10,000 population (if theyare outside the commuting influence of a large urbancentre). The operating speeds are generally greaterthan 70 km/h. The basic limitation on vehicleoperation lies with the motorist. Even if the operatingspeed is less than 70 km/h, treatment of the situationas a free flow case recognizes that the drivingcharacteristics in small communities are different thanthose in large urban areas

Roadway Type:

The minimum justification values for the volumeon the main road are for a two-lane, two-wayroadway. Vehicle volume justifications for multi-lane roadways having four or more through laneson the main road should be 25% higher. Two-lane,two-way roadways with exclusive left-turn lanes arenot classified as multi-lane roadways.

Entering Vehicles:

Only vehicles entering the intersection – whether theyturn right, go straight through or turn left – should beconsidered. If the right turns are channelized andeffectively segregated from the through traffic bymeans of a physical island, right-turning vehicles arenot considered to enter the intersection and thereforeshould not included in any justification calculations.

Bicycles:

For the purposes of traffic control signal justificationanalysis, bicycles shall be treated as vehicles whenon the road and included in vehicle volume counts assuch; bicycles shall be treated as pedestrians at theintersection of roads and park paths where cyclistsdismount to cross the road.

4.4 Justification 1 - Minimum VehicleVolume

Purpose

The Minimum Vehicular Volume Justification isintended for applications where the principal reasonto consider the installation of a traffic control signal isthe cumulative delay produced by a large volume ofintersecting traffic at an unsignalized intersection.

Justification 1A reflects the lowest total traffic on allapproaches and Justification 1B reflects the lowestvolume on the minor road for which the average delayis similar for both signalized and unsignalizedconditions. Therefore, this justification is intended toaddress the minimum volume conditions in whichsignalization can be used to minimize total averagevehicle delay at the intersection.

As volumes increase over the threshold criteria, delayto traffic on the minor road will increase such thatthe overall vehicle-hours of delay for the intersectionwould be greater than if minor delays were distributedamong both roadways.

Standard

The need for a traffic control signal shall be consideredif both Justification 1A and Justification 1B are 100%fulfilled.

If Justifications 1A and 1B do not surpass 100% butare at least 80% fulfilled, the lesser fulfilled of theJustifications 1A or 1B can be used in the assessmentof Justification 4, the Combination Justification.

In applying Justification 1 (Minimum Vehicle Volume )for “T” intersections, the justification values for the minorstreet are increased by 50%. This reflects the reductionin potential conflicts between left turns and throughmoves on the minor road with the elimination of oneof the approaches.



Table 12 shall be used for Restricted Flow (Urban)Conditions, while Table 13 is applicable to the FreeFlow (Rural) case (see Section 4.3.2 for definitions).

Guidelines

“Average Compliance” is calculated in Tables 12 & 13for reference purposes, and may indicate how close anintersection is to achieving full justification. “AverageCompliance” is calculated by adding all 8 hourcompliance percentages and dividing that value by 8.The Compliance % figures used in Table 12 & 13 mustnot exceed 100%.

4.5 Justification 2 - Delay To CrossTraffic

Purpose

The Delay to Cross Traffic Justification is intended forapplication where the traffic volume on the main roadis so heavy that traffic on the minor road suffersexcessive delay or hazard in entering or crossing themain road.

Standard

The need for a traffic control signal shall be consideredif both Justification 2A and Justification 2B are 100%fulfilled. If Justifications 2A or 2B do not surpass100% but both are at least 80% fulfilled, the lesserfulfilled of the justifications 2A or 2B can be used inthe assessment of Justification 4, the CombinationJustification.

Table 14 (p.72) shall be used for Restricted Flow(Urban) conditions, while Table 15 (p.73) applies tothe Free Flow (Rural) case (see Section 4.3.2 fordefinitions).

Table 12 - Justification 1 - Minimum Vehicle Volume for Restricted Flow (Urban) Conditions

SEE JUSTIFICATION 4

AverageCompliance

%

AverageCompliance

%

* * Note: The compliance % figures used in Table 12 & 13 must not exceed 100%.

JUSTIFICATION

1A

1B

GUIDANCE

COMPLIANCE % * *

COMPLIANCE % * *

TOTAL TRAFFIC VOLUMEENTERING INTERSECTION

(vph) (2 way Total)

CROSSINGTRAFFIC VOLUME(vph) (2 way Total)

(RESTRICTED FLOW)

SIGNAL JUSTIFICATION 1:

HOUR ENDING

> 100% > 80%

No. of hourswith compliance

= VOL x 100720

(1 laneapproach onmain road)

= VOL x 100255

(tee intersection)

= VOL x 100900

(2 or more laneapproach onmain road)

OR

OR= VOL x 100170

(full intersection)

BOTH 1A AND 1B 100% FULFILLED EACH OF 8 HOURS

LESSER OF 1A OR 1B AT LEAST 80% FULFILLED EACHOF 8 HOURS

YES

YES

NO

NO



Guidelines

Right turns are not considered as traffic crossing aroad; therefore they should be deleted from thecombined pedestrian and vehicle volume in the Delayto Cross Traffic Justification. In one-way street systemsleft turns from a one-way street into another one-waystreet should be treated in a similar manner to rightturns and be deleted from the justification.

When applying Justification 2B, the crossing volumeconsists of the sum of:

1. The number of pedestrians crossing the mainroad; plus

2. Total left turns from both the side roadapproaches; plus

3. The highest through volume from one of theside road approaches; plus

4. 50% of the heavier left-turn traffic movementfrom the main road when both of thefollowing two criteria are met :

a)The left-turn volume is greater than 120vehicles per hour; and

b)The total of the left-turn volumes plus theopposing volume is greater than 720 vehiclesper hour.

“Average Compliance” is calculated in Tables 14 and15 for reference purposes, and may indicate how closean intersection is to achieving full justification.

The Compliance % figures used in Tables 14 and 15should not exceed 100%

Table 13 - Justification 1 - Minimum Vehicle Volume for Free Flow (Rural) Conditions

SEE JUSTIFICATION 4

AverageCompliance

%

AverageCompliance

%

* * if calculated compliance % > 100%, show as 100% in table

JUSTIFICATION

1A

1B

GUIDANCE

COMPLIANCE % * *

COMPLIANCE % * *

TOTAL TRAFFIC VOLUMEENTERING INTERSECTION

(vph) (2 way Total)


(FREE FLOW)


HOUR ENDING

> 100% > 80%


= VOL x 100480

(1 laneapproach onmain road)

= VOL x 100180

(tee intersection)

= VOL x 100600

(2 or more laneapproach onmain road)

OR

OR= VOL x 100120

(full intersection)


LESSER OF 1A OR 1B AT LEAST 80% FULFILLED EACHOF 8 HOURS

YES

YES

NO

NO



4.6 Justification 3 - CollisionExperience

Purpose

Where an unsignalized intersection has an unusuallyhigh collision record, signalization may be consideredas one means of improving intersection safety.

Standard

While a collision situation alone seldom justifies signalcontrol, the installation of traffic control signals maybe justified when every one of the following conditionsas presented in Table 16 (p.74) is satisfied:

1. Five or more reportable collisions of typespreventable by traffic control signals haveoccurred during each of the three precedingtwelve month periods, each collision involvingpersonal injury or property damage whichappears to be serious enough to be reported to

police. Preventable collisions are thoseinvolving vehicles which under signalizedconditions would move on completelyseparate approaches.

2. Adequate trial of less restrictive remedieswith satisfactory observance and enforcementhave failed to reduce collision frequency.

3. There exists a volume of vehicular andpedestrian traffic not less than 80% of therequirements specified in the MinimumVehicular Volume Justification 1, or the Delayto Cross Traffic Justification 2.

Guidelines

Less restrictive measures which could be tried beforesignals are installed include the improvement of controlor warning signs, installation of flashing beacons, theprovision of safety or channelizing islands, theimprovement of streetlighting, geometric or visibilityimprovements, shifting of bus stops, and/or theprohibition of parking and/or turns.

Table 14 - Justification 2 - Delay To Cross Traffic for Restricted Flow (Urban) Conditions

SEE JUSTIFICATION 4

AverageageComplianceCompliance

%

AverageageComplianceCompliance

%

JUSTIFICATION

2A

2B

GUIDANCE

COMPLIANCE %

COMPLIANCE % * *

MAIN ROADTRAFFIC VOLUME(vph) (2 way Total)


(RESTRICTED FLOW)

SIGNAL JUSTIFICASIGNAL JUSTIFICATION 2:TION 2:

HOUR ENDING

> 100% > 80%


= VOL x 100720

(1 laneapproach)

= VOL x 100900

(2 or more laneapproach)

OR

= VOL x 10075

BOBOTH 2A AND 2B 100% FULFILLED EATH 2A AND 2B 100% FULFILLED EACH OF 8 HOURSCH OF 8 HOURS

LESSER OF 2A OR 2B ALESSER OF 2A OR 2B AT LEAST 80% FULFILLED EAT LEAST 80% FULFILLED EACH CH OF 8 HOURS OF 8 HOURS

YES

YES

NO

NO




When applying this Justification, the analyst shouldconsider that where self-reporting of collisions (asopposed to the once-standard documentation at thescene by police) is prevalent, it will have the effect ofintroducing less accuracy into the determination ofwhether or not the collision was preventable bysignals.

The Justification is intentionally designed so thatinstallation of traffic signals will seldom be justifiedon the collision justification alone. Engineeringjudgement should be applied to assess whether signaluse may even increase the intersection collision ratedue to rear-end collisions, etc., caused directly orindirectly by the signal operation.

4.7 Justification 4 - CombinationJustification

Purpose

Signals may occasionally be justified where neither ofJustifications 1, 2 nor 3 are 100% satisfied, but twoor more are satisfied to the extent of 80% or more ofthe stated values, particularly if the other importantfactors are present such as:

• Sudden change from rural conditions to thoseof urban commercial surroundings;

• Extreme width of roadway which pedestriansmust cross;

• Predominance of small children, seniors ordisabled pedestrians who need to cross theroadway; and,

• Increasing traffic volumes.

Table 15 - Justification 2 - Delay To Cross Traffic For Free Flow (Rural) Conditions

SEE JUSTIFICATION 4

AverageCompliance

%


AverageCompliance

%

JUSTIFICATION

2A

2B

GUIDANCE

COMPLIANCE %

COMPLIANCE % * *

MAIN ROADTRAFFIC VOLUME(vph) (2 way Total)


(RESTRICTED FLOW)


HOUR ENDING

> 100% > 80%


= VOL x 100480

(1 laneapproach)

= VOL x 100600

(2 or more laneapproach)

OR

= VOL x 10050


LESSER OF 2A OR 2B AT LEAST 80% FULFILLED EACH OF 8 HOURS

YES

YES

NO

NO



Standard

The requirements for the Combination Justification aregiven in Table 17.

Guidelines

For the purposes of the Combination Justification,Justification 3 (Collision Experience) is considered tobe met 80% if Justification 3A exceeds 80% andJustification 3B is met 100%.

4.8 Justification 5 - Pedestrian Volumeand Delay

Purpose

The minimum pedestrian volume conditions areintended for application where the traffic volume ona main road is so heavy that pedestrians experienceexcessive delay or hazard in crossing the main roador where high pedestrian crossing volumes producethe likelihood of such delays.

Table 16 - Justification 3 - Collision Experience

Table 17 - Justification 4 - Combination Justification

YES NO

YES NO

YES NO

SIGNAL JUSTIFICASIGNAL JUSTIFICATION 1:TION 1: ALL OF A, B AND C ABOVE FULFILLED TO 100% ?

A.A. Number of reporNumber of reportabtable collisions susceptible collisions susceptible to prele to prevention bention by a try a traffic signal.affic signal.

C. Either JEither Justification 1 (Minimustification 1 (Minimum um Vehicular ehicular Volume) or Jolume) or Justification 2ustification 2(Dela(Delay to Cross y to Cross Traffic) satisfied to 80% or moreaffic) satisfied to 80% or more.

B. Adequate trAdequate trial of less restrial of less restrictive remedies has fe remedies has failed to reduce ailed to reduce collision frequencycollision frequency.

PrecedingMonths

Numberof

Collisions

% Fulfillment> 5 100% 4 80%< 3 0%

1 - 1213 - 2425 - 36

TOTAL = 3 %

100% 0%

100% 0%

100% 0%

YES NO YES NO

YES NO

YES NO JUSTIFIED NOT JUSTIFIED

Justification 1 - MinimMinimum um Vehicular Volumeolume

Justification 2 - Delay to Cross y to Cross Traffic

Justification 3 - Collision Experience

JUSTIFICAJUSTIFICATION SATION SATISFIED 80% OR MORETISFIED 80% OR MORETwo Justifications

Satisfied 80% or moreSatisfied 80% or more



The justification may occur at either an unsignalizedintersection or at a mid-block location.

Once a justification has been established, determinationof the appropriate crossing protection device shouldbe subject to site-specific engineering judgement (seeGuideline 3 for options).

Standard

The need for a traffic control device at an intersectionor mid-block location shall be considered if both thefollowing minimum pedestrian volume and delaycriteria are met:

1. The total 8-hour pedestrian volume crossingthe main road at an intersection or mid-blocklocation during the highest 8 hours ofpedestrian traffic fulfils the justificationrequirement identified in Table 20 (p.76) ; and

Table 18 - Pedestrian Volume Data Summary

Table 19 - Pedestrian Delay Data Summary

ZONE 1ZONE 1TOTALAL

ASSISTED * UNASSISTED ASSISTED UNASSISTED ASSISTED UNASSISTED ASSISTED UNASSISTED

8 HOUR PED8 HOUR PED.VOLUME COUNTOLUME COUNT

FACTCTORED 8 HOURORED 8 HOURPEDPED. VOLUME OLUME ¥ ¥

% ASSIGNED % ASSIGNED TOCRCROSSING RAOSSING RATE * * *TE * * *

NET 8 HOUR PEDESTRIAN NET 8 HOUR PEDESTRIAN VOLUME AOLUME AT CRT CROSSINGOSSING

NET 8 HOUR NET 8 HOUR VEHICULAR VEHICULAR VOLUME ON STREET BEING CROLUME ON STREET BEING CROSSED OSSED

* "Assisted" = Senior Citizens, Disabled Pedestrians and children under 12 Assisted in Crossing the Road* * Factored Volume = (Unassisted) + (2 x Assisted) Volume* * * See Guideline No.1

ZONE 2 (if needed)ZONE 2 (if needed) ZONE 3 (if needed)ZONE 3 (if needed) ZONE 4 (if needed)ZONE 4 (if needed)

ZONE 1ZONE 1 TOTALAL

ASSISTED * UNASSISTED ASSISTED UNASSISTED ASSISTED UNASSISTED ASSISTED UNASSISTED

FACTCTORED ORED VOLUME * *OLUME * *OF OF TOTAL PEDSAL PEDS.

8 HOUR 8 HOUR TOTAL OF PEDSAL OF PEDS.DELADELAYED > 10 SECONDSYED > 10 SECONDS

8 HOUR 8 HOUR TOTAL OF PEDSAL OF PEDS.

FACTCTORED ORED VOLUME * *OLUME * *OF DELAOF DELAYED PEDSYED PEDS.

% ASSIGNED % ASSIGNED TOCRCROSSING RAOSSING RATE * * *TE * * *

NET 8 HOUR NET 8 HOUR VOLUME OF OLUME OF TOTAL PEDESTRIANSAL PEDESTRIANS

NET 8 HOUR NET 8 HOUR VOLUME OF DELAOLUME OF DELAYED PEDESTRIANSYED PEDESTRIANS

* "Assisted" = Senior Citizens, Disabled Pedestrians and children under 12 Assisted in Crossing the Road* * Factored Volume = (Unassisted) + (2 x Assisted) Volume* * * See Guideline No.1

ZONE 2 (if needed)ZONE 2 (if needed) ZONE 3 (if needed)ZONE 3 (if needed) ZONE 4 (if needed)ZONE 4 (if needed)



2. The total 8-hour volume of pedestriansexperiencing delays of ten seconds or more incrossing the road during the highest 8 hoursof pedestrian traffic fulfils the justificationrequirement identified in Table 21

The graphed equations used in Tables 20 and 21 areincluded for reference purposes as Figures 12 (p.78)and 13(p.79).

Guidelines

1. If a roadway is crossed by pedestrians inseveral locations and the introduction of asignal-protected crossing is likely to serve toconsolidate the crossings at a single point,the road segment may be divided into zonesand appropriate proportion of crossings ineach zone reassigned to the signal-protectedcrossing zone. (See “% Assigned to CrossingSite” in Tables 18 and 19)

Table 20 - Pedestrian Volume Justification 5A

Table 21 - Pedestrian Delay Justification 5B

< 1440< 1440

< 200< 200 200 - 275200 - 275 276 - 475276 - 475 476 - 1000476 - 1000 > 1000> 1000

1440 - 26001440 - 2600

2601 - 70002601 - 7000

> 7000> 7000

8 Hour 8 Hour VehicularehicularVolumeolume

V8

Net 8 Hour PNet 8 Hour Pedestredestrian ian Volumeolume

EQUATION 1: Justified ifif net 8 hour ped. vol. > (1650 - (0.45V8))

EQUATION 2: Justified ifif net 8 hour ped. vol. > (0.0001 V82 - 0.146V8 + 770)

EQUATION 3: Justified ifif net 8 hour ped. vol. > (340 - (.0094V8))

% Justification = ((net 8 hour pedestrian volume) / (Equation 1, 2 or 3 as appropriate)) x 100 %

Not Justified

Not Justified

Not Justified

Not Justified

Not Justified

Not Justified

Not Justified

See Equation 3

Not Justified

Not Justified

See Equation 2

Justified

Not Justified

See Equation 1

Justified

Justified

Not Justified

Justified

Justified

Justified

< 200< 200

< 75< 75 75-13075-130 > 130> 130

200-300200-300

Net Net Total 8 Hour otal 8 Hour Vol.ol. of ofTotal Potal Pedestredestriansians

Net Net Total 8 Hour otal 8 Hour Volume of Delaolume of Delayed Ped Pedestredestriansians

% Justification = ((net 8 hour delayed pedestrian volume) / (threshold volume for justification)) x 100 %

Signal Justification:Both Justification 5A (volume) and Justification 5B (delay) met?

Not Justified

Not Justified

Not Justified

Not Justified

Justified ifif vol. of delayedpeds > (240 - (.55 x vol. of total

peds))

Justified

Not Justified

Justified

Justified

YES

NO

= Traffic Control Justified

= Traffic Control Not Justified

> 300> 300



2. In the case of a divided roadway with a raisedmedian of at least 1.2m in width, thejustification may be calculated separately foreach direction. The “worst case” directionwill govern the outcome, such that if aprotected crossing is justified in one directionthe entire crossing will be justified.

3. If both Justification 5 and a trafficengineering study determine that protection ofpedestrian traffic crossing a roadway isappropriate, consideration may be given to thevariety of options available. Consistentmunicipal practice is desirable in terms ofpedestrian crossing types, applicationthresholds and crossing design. This relatesto the need for motorist familiarity with thecrossing of running the signal or undertakingother unsafe manoeuvres. Application of asingle use of one crossing type should beavoided. The available pedestrian crossingprotection devices include:

a) Intersection Pedestrian Signals (IPS)If the pedestrian crossing under consideration is tobe at an intersection, justification should be made onthe basis of Justification 5 being fulfilled but thecrossing vehicular traffic should be so light as to notmeet one of the other justifications (1 - 4).

b) Pedestrian Crossovers (PXOs)Pedestrian Crossovers are intended for low tomoderate volume, low speed roadways (60km/h orless posted speed) and shall not be used where theroad volume exceeds 35,000 AADT. PXOs shouldnot be installed at sites where there are heavyvolumes of turning traffic, or where there are morethan four lanes of two-way traffic or three lanes ofone-way traffic. PXOs should not be within 200 mof other signal-protected pedestrian crossings.Parking and other sight obstructions should beprohibited within at least 30 m of the crossings.Regulation 615 of the HTA covers most aspects.

Justification for PXOs should be based on the abovefactors plus a percent justification of that given inTables 20 and 21, which is set by the authority as thethreshold of need.

c) Midblock Pedestrian CrossingsMidblock pedestrian crossings should be restrictedto roadways posted at less than 80 km/h.

Justification for Midblock pedestrian signals shouldbe based on a percent justification, as given in Tables19 and 20, which is set by the authority as thethreshold of need.

d) Full Intersection SignalsConsideration should be given to implementing a fulltraffic control signal at an intersection in the casewhere pedestrian crossing protection is justified but :

• a PXO, IPS or Midblock Device isinappropriate because of the roadwayphysical or operating conditions as notedin (a) or (c) above; or

• an IPS is justified but is not in use withinthe municipality.

In such cases, it is desirable that at least one of thejustifications 1, 2 or 3 is met 80% or more in additionto justification 5 being met.

e) Pedestrian Grade Separations

In cases of very heavy pedestrian and traffic volumes,it may be economically viable to construct pedestrianbridges or tunnels.

4. The priority placed on implementing a newpedestrian crossing device should reflect theproximity and convenience of existingcrossings; a higher priority should be placed oncrossings where no reasonable alternatives existwithin walking distance.



4.9 Signal Justifications For FutureConditions

The prediction of future traffic requirements within a 5year period is based on knowledge of roadway usagegrowth, growth of local traffic generators and predictedtraffic volumes .

Future hour-by-hour 8 hour volumes are difficult topredict with the necessary accuracy; thereforejustifications for future conditions normally use theDesign Hourly Volume (DHV) or peak hour volumesfor the intersection.

Due to the increased uncertainty of volume projectionsfor proposed new developments, an increasedjustification threshold is used in those cases.Justification 1 and Justification 2 are used only andthe recommended increase is 20% in the case of anexisting intersection and 50% in the case of a newintersection.

As noted in Section 5, where a signal is anticipated tobe justified within five years of roadway construction,recommended practice is to construct the necessaryunderground provisions as part of the road works.

Figure 12 - Pedestrian Justification Based on Pedestrian Volumes

Note : Use Factors of 2.0 toAdjust For SeniorCitizens, DisabledPedestrians AndUnassisted Children



4.10 Signal Installation Prioritization

On a network-wide scale, funding limitations or otherconstraints may lead to an inability to implement all signalswhich meet the minimum technical justification criteria.It is therefore important to understand the relative valueof each candidate set of traffic control signals so thateffort maybe directed first to the site which would providethe greatest overall benefits. The benefits are normallyexpressed in terms of benefit/cost ratios with safety andthe movement of people and goods the primeconsiderations.

The weighting placed on each of the justificationcomponents in terms of priority is the responsibilityof the signal authority. There are several softwarepackages available that will carry out prioritization.One basic manual approach is to prepare acombination justification analysis for each potentiallocation and rank the sites by the degree to whichthey meet the combination justification as shownin Table 24 (p.85). This approach has the effect ofensuring collision history is integrated into theprioritization process.

Figure 13 - Pedestrian Justification Based on Pedestrian Delay

Note : Use Factors of 2.0 toAdjust For SeniorCitizens, DisabledPedestrians AndUnassisted Children



This figure may be further weighted by benefit / costratio, or by the capital cost of the installation relativeto the average signal installation cost in the jurisdiction,or by other locally-generated factors. The ratings foreach site are then tabulated and ranked from highestto lowest in terms of “Average” combined justification.

Table 23 - Signal Installation Prioritization

4.11 Table 22 - Summary of Signal Justification

Justification ComplianceCompliance

Signal Justified?

MET? YES NO

1. Minimum Vehicular Volume

2. Delay to CrossTraffic

3. CollisionExperience

4. Combination

5. Pedestrian

A Total Volume > 100% _____ of 8 hours

> 100% _____ of 8 hours

> 100% _____ of 8 hours

> 100% _____ of 8 hours

> 80% 8 of 8 hours

> 80% 8 of 8 hours

> 80% 8 of 8 hours

_____ %

_____ %

_____ %

YES / NO

B Crossing Volume

A Main Road

B Crossing Road

A Collisions

B Trial of Remedies

A Volume

B Delay

Overall At least one Justifications 1 - 5 met?

B Delay Justification 2

C Collisions

C Justification 1 or 2Compliance

A Minimum VolumeJustification 1

3A > 80%AND

3B = YES

Justification 1A Compliance for Avg. Hour ______%

Justification 1B Compliance for Avg. Hour ______%

Justification 2A Compliance for Avg. Hour ______%

Justification 2B Compliance for Avg. Hour ______%

Justification 3 Condition A Fulfilment ______%

Justification 4A Compliance ______%

Justification 4B Compliance ______%

"Average" Combined Justification ______%



4.12 Justification for Temporary TrafficControl Signals

Temporary traffic control signals shall be justified foruse in the following locations:

1. Where either road at an intersection has aposted speed of 80 km/h or greater andconstruction staging does not allow theexisting poles to be kept at the proper clearzone, nor does it allow for protection of thepoles with barrier.

2. Where either road at an intersection has aposted speed of 80 km/h or greater and thevisibility of the traffic signal heads will notmeet the design criteria for visibility, as givenin Section 5, where traffic is moved from itsnormal lanes and where 24 hour flag persons,barriers and other devices are not practical tomaintain; and

3. Where pedestrian visibility of pedestriansignal heads may be obscured byconstruction equipment and/or re-routing ofpedestrian crossings and the possibility ofconfusion or pedestrian interference withconstruction activities exists (temporarypedestrian heads may be sufficient).

4.13 Justification for Bicycle Signals

This subsection may be added in future.

4.14 Removal of Existing Signals

If the conditions under which a signal was installedchange significantly and concerns arise that it is nolonger justified, it may be analysed using Justifications1 - 5 on the same basis as if it were a “new”installation. If, under current conditions, the signal failsto meet any of Justifications 1 -5 then it should beconsidered a candidate for removal. If onlyJustification 5 is met, then the installation should bereviewed to ensure that the most appropriate type ofpedestrian crossing protection is used. Removal of asignal should not take place without consultation withthe affected community.



5. Design Practice

5.1 General

Use Of This Section

Each road authority may have their own specificdesign requirements. Designers should refer to theauthority’s documents for design as this section ofthe manual provides only general design requirements.

This section of the manual is intended to providegeneral design interpretation, recommended practiceand guidance for the design of traffic signals. Thedesign practices and guidelines given in this sectionare intended to have the following objectives:

• provide a standardized basis of designthroughout Ontario;

• provide instructional value to designers ofMinistry and municipal traffic control systems;

• suggest standard practice details for use bymunicipalities not having standards;

• comment on some non-standard practices,conditional on the nature of the intersectionand the traffic;

• provide some pragmatic recommendations inthe detail design of traffic control signallayouts.

The design guidelines in this section are based onnew construction or reconstruction of intersectionssince that is the most common situation The designguidelines may be easily adapted to suit existingconditions where there is no roadway workcontemplated.

5.2 Practical Requirements

The responsibility of the designer is to produce a safe,ef fective and ef ficient signal design which isacceptable to the road authority, enables provision ofacceptable levels of service and delay standards tomotorists, meets recognized standards and is practicalin the following areas:

• free of utility interference;

• meets signal head visibility requirements;

• compatible with the roadway, pavementstructure and roadside works;

• uses standardized equipment;

• is readily expandable to additional phases ormovements within the foreseeable 5 yearperiod as identified by the Needs orJustification Reports.

It is acknowledged that there are sometimeslimitations imposed by boulevard conditions, sidewalklocations and underground and overhead utilitieswhich may make it infeasible to abide by all thepractices and guidelines given. In such cases, somecompromise is normally necessary and soundengineering judgement shall be used to arrive atdesigns which follow the practices and guidelines asclosely as practical.

5.3 Safety Considerations

Safety considerations for the detailed design of trafficsignals include the following factors:

• adequate pole offsets from the edge of thethrough lanes of pavement as related to theposted speed. The recommended practiceuses a 3.0 m offset; a minimum offset of 1.5m from the face of curb is suggested in urbanareas of 50 km/h or less with 0.6 m being theabsolute minimum for use at posted speeds of40 or 50 km/h;



• the use of pole types which meet therequirements of the safety clear zones asgiven in the Ministry’s Roadside SafetyManual22 and in municipal policy manuals;

• adequate vertical clearance to traffic signalheads and overhead wiring such that they areelectrically safe and free from vehicleinterference;

• proper fusing or circuit breaker ratings infeeders to electrical devices;

• proper main disconnecting devices for thepower to the controllers;

• proper electrical grounding of the electricalpower devices, poles and equipment.

The detailed requirements for the above maybe foundin the Ministry’s Electrical Engineering Manual2,3

series, municipal practice manuals and in otherreferenced documents.

5.4 Future Considerations

The prediction of future traffic volumes within a 10year period is based on an anticipated future trafficdemand. A traffic control signal Needs Report orJustification Report should be prepared whichaddresses not only current traf fic volume andintersection capacity analysis, turning needs andpedestrian needs, but also the five year horizon forsuch needs and the possibility of roadwayreconstruction and/or lane reconfiguration.

If it can be confirmed that the intersection will beupgraded for roadway deficiency reasons within a fiveyear time frame, then the designer should inquire asto future plans for the intersection since currentreconstruction of signals may require basic changesto pole footings, pole types, wiring and controllerequipment. If plans are reasonably firm for the future,

the traffic signal designer should request the roadplanner/designer to provide any features required inthe future that could possibly be incorporated into thecurrent design.

If future reconstruction of the intersection is requireddue to the growth of traffic or due to changes to travelpatterns in the area, and this is confirmed by trafficstudies, then the traffic signal designer should seekadvice from knowledgeable persons such as roadplanners/designers. Overbuilding of the traffic signalsmay be a waste of money if many features will requirefuture reconstruction in any event. Conversely, if firmplans for future intersection geometry are available, itwould be advisable, where practical, to locate itemssuch as electrical chambers and ducts in the locationsrequired for the future reconstruction, or, in some cases,it may even be advisable to design aerial traffic signalsas an interim measure.

Where traffic control signal studies indicate that trafficcontrol signals are not required at the time ofconstruction/reconstruction of the intersection, but willbe required within five years, then the recommendedpractice is to construct underground provisions, in theform of ducts and electrical chambers within the currentintersection upgrade. Pole footings should only beconstructed where traffic at the intersection will begrossly increased within a two year time frame due tothe construction of a new shopping mall or other largetraffic generator.

5.5 Signal Visibility

General

Signal visibility, for ease of comprehension, is themost important aspect of traffic control signaldesign. The recommended practices and guidelinesgiven in this section should be seriously consideredand followed as closely as possible.



The visibility of signal indications, outside of geometricconsiderations, are related to the following:

• location of the signal heads and their visibilityand conspicuity when illuminated;

• lamp ratings, lumen output and age;

• reflectors and refractors;

• dirt accumulation on the optical system;

• “Sun phantoms” causing the lenses to appearilluminated through reflections of the sun; and

• type of optical system (standard, opticallyprogrammed, LED, fibre optic).

Signal Head Locations

The effectiveness of any traffic control signal installationwill largely depend on the ease with which the signalheads can be seen and recognized, especially bymotorists passing through the intersection for the firsttime. Motorists should not be forced to search for thesignals or to take their attention away from the road inorder to see the signal indications.

The signal indications should be immediately and easilynoticeable. The state of being noticeable, or theconspicuity of the signals, is affected by the followingfactors:

• at least one signal head should be within themotorists’ cone of vision extending 30o

horizontally and 15o vertically from the eyeswhen facing straight ahead. This requirementapplies from the sight distance required forvisibility (Table 24 subsection 5.5). Therequirement at the stop line ensures that the redsignal indication is visible by the motoristthrough the windshield;

• Figure 14 shows application of thehorizontal cone of vision. Where thehorizontal and vertical geometry are not aproblem, the cone of vision may be tested atthe stopline. (This is the worst case since thecone encompasses more width at a greaterdistance);

• where horizontal or vertical geometryprohibits visibility of at least one signal headwithin the cones of vision from the visibilitydistance of Table 25, the use of an auxillarysignal head and / or a continuous oractivated flasher / “signals ahead” sign maybe required;

• geometry of the roadway and the combinedeffects of horizontal and vertical alignmenton vision from the intersection approaches;

• visual obstructions or distractions due tobuildings, signs, etc. adjacent to the right-of-way;

• colours of the signal heads and backboardsin contrast with the colour of theirbackground;

• standardized locations so that the majority ofmotorists, who are residents of Ontario, willnot be confused and will not have to visuallysearch for the signal heads.

A minimum of two signal heads shall face eachapproach of the intersection, including public-usedriveways within the intersection. At typicalintersections, signal heads may be mounted on poleswith double arm brackets, suspended over thepavement on mast arms, gantry arms or structuralframes, or mounted on span wire over the far side ofthe intersection approach.

Many intersections exhibit geometric characteristicswhich do not lend themselves to obtaining goodvisibility and alternative or auxiliary methods mustbe explored. For good visibility of signal heads, theguidelines should be considered and followed asrigidly as possible.



Viewing Angles

The optimum viewing zone for traffic signal heads iswithin 15o horizontally or vertically. This gives ahorizontal cone of vision of 30o and at least one signalhead should be within this cone, in the area betweenthe visibility sight distance and the stop line, as shownin Figure 14.

Lateral Signal Head Locations

A primary signal head must be located on the far rightside of the intersection facing each vehicle approachto the intersection.

The primary signal head should be located laterally atleast at the edge of pavement (0.5 m over the roadwaypreferred), at intersections with a signal head on amedian island. Where median islands do not exist,the primary signal heads should be located at the 1/2to 3/4 point of the curb lane.

The secondary signal heads must be located on theleft of approaching through lanes, on the median orthe far left side of the intersection at least at the edgeof pavement. Where intersection approaches do notalign, these references may be taken on the near sideof the intersection.

The secondary heads (far left side) should be locatedat or as close to the edge of the roadway as practical.

Figure 14 - Cones of Vision for Signal Visibility

Table 24 - Signal Visibility Distances

STOP LINE

1.2 m30¼

VISIBILITY DISTANCE



Backboards

Backboards are recommended for all primary headsand are preferred on all heads except secondary headsused at very low posted speeds of 50 km/h and less.

Table 25 gives typical applications for the use of variouscombinations of signal head and backboards withoutarrow control.

Backboard faces shall be traffic yellow in colour undermost conditions. Specific conditions may exist wherethe daytime target value or visibility and conspicuityof the backboard faces may be enhanced by use of adark colour such as dark green or black. Thesesituations normally occur where the signal heads areat the top of a hill and have a sky background.

Median Mounted Signal Heads

Signal heads mounted on median poles may bemounted either on the front of the pole or side mountedto give better target value to the heads. Variations arenecessary for signal heads with left-turn arrows andmast arms, multiple heads on a pole and geometricvariations.

Visibility Distance

Motorists approaching a signal must be able to seethe signal indications in sufficient time to react and totake any necessary actions. At least one signal headmust therefore be visible from a distance as indicatedin Table 24.

Table 25 - Typical Use of Signal Heads and Backboards

PostedSpeed(km/h)

Type ofRoadway

SignalHead

Type ofHead

Backboard RecommendedMountingHeight (m)

Signal Heads and Backboards

Major Roadway(Four or more

lanes)

Minor Roadway(Less than four

lanes)

80 and over

60 to 80

less than 60

60 to 80

less than 60

80 and over

Primary

Secondary

Primary

Secondary

Primary

Secondary

Primary

Secondary

Primary

Secondary

Primary

Secondary

Highway

Highway

Highway

Highway

Highway

Highway

Standard

Highway

Highway

Highway

Highway

Highway

Standard

Highway orStandard

Yes

Yes

Yes

Yes

Yes

Yes

Optional

Yes

Yes

Yes

Yes

Yes

Yes

Optional

5

5

5

5

5

2.75*

5

5

5

5

5

2.75*

* for signal heads not over traffic lanes



The rear surfaces of backboards are considered to beof little significance to the visibility of signals. Standardtraf fic yellow is used in most situations butmunicipalities may prefer to apply black or silvercolours to the rear sur faces as long as thecorresponding signal head housings are of the samecolour and as long as the application is consistent forany particular intersection.

Mounting Height

Signal head mounting heights are legally set underthe Highway Traffic Act and are given in Section 2Legal Requirements.

Secondary heads mounted on the far left and notover traffic lanes may be mounted at a minimumheight of 2.75 m for roadways posted at less than 80km/h. Secondary heads for roadways posted at 80km/h or more are preferred to be at the same heightas the primary head for long range visibility reasons.Where a secondary head is installed in a median islandand where the left-turn lane is often blocked by largevehicles, auxiliary heads may be used on the far leftof the intersection to allow better visibility. Auxiliaryheads may be mounted at a minimum height of 2.75m or as high as necessary to obtain good visibility.The desirable height in most cases is still 5.0 m. ForKing’s Highways and other roads posted at 80 km/hand over, all signal heads should be mounted at 5.0m clearance height.

Obstruction By Other Signal Heads

As well as trees, signs,etc., the secondary signal headfacing opposing traffic could possibly act as a sightline obstruction for a considerable travel distance asshown in Figure 15. A straight edge should be usedon the plan to ensure that the near side secondaryhead is not blocking the far side primary head andthat at least one signal head is visible at all times, asseen by the motorist from the distances given in Table24 and from all points between that distance and theintersection. A field check of these requirements isrequired during installation.

Figure 16 - Auxillary Heads at Underpass

Figure 17 - Auxillary Heads at Intersectionon Curve

Figure 15 - Secondary Head Blocking Visibility

SIGNAL HEAD "A" SHOULDBE TO THE LEFT OF HEAD"B" BY A MINIMUM OF 1.0m

CORRECT

INCORRECTA

1.0m Min.

DISTANCE AS PER TABLE 24

VISIBILITY CRITERIA APPLIES IN ALLLANE LOCATIONS FROM HERE TO

THE STOP LINE

B

BRIDGE

BRIDGE

HIGHEST SIGHT LINE

PLAN

PROFILE

DISTANCE AS PER TABLE 25

NORMALHEADS

AUXILIARYHEADS

A,BC,D

C

D

A

B

AUXILIARY HEADPREFERRED LOCATION

15¼ MAX

ALTERNATIVELOCATION

LINE OF SIGHT TO SIGNAL ISOUTSIDE MOTORIST'S CONEOF VISION



on other features such as pavement marking changes,signage or off-roadway distractions. Auxiliary headsmay be required on the near side of the intersectioneither on the outside of the curve or the rear of themedian pole as shown of Figure 17 (page 87).

Two auxiliary heads on the outside of a curveshould be avoided since the gap between them maybe mistaken as the roadway during limited visibilityconditions.

Care should also be taken with horizontal and verticalroadway curvature which is made visually abrupt.Visibility along horizontal curves may be hamperedby buildings, rock cuts or large signs along the insideof the curve. Here, auxiliary heads at the intersectionwill be needed on the outside of a horizontal curve.Similarly, abrupt vertical curves which do not allow aview of the intersection pavement at the stopping sightdistance may require auxiliary heads either at theintersection or at a much higher mounting height.

This situation is particularly bad where trees enter intothe sight lines (sag curves) or opposing vehicleheadlights produce high glare at night (crest curves).Also, combinations of horizontal and vertical geometrycan produce rather treacherous results to designswhich appear satisfactory on plan view. Only plottingof the sight lines on both plan and profile will show

Auxiliary Signal Heads And Beacons

General

Signal heads may be obstructed by bridges (where abridge is too close to an intersection),by horizontalroadway curvature, by vertical roadway curvature, byother signal heads, by signs, by buildings infringingon a zone of restricted right-of-way, by large vehiclesdue to poor spacing of the signal heads and bycombinations of many of these features.

Auxiliary signal heads are installed in addition to, andas a visual aid to the primary signal head and thereforeauxiliary signal heads must display the sameindications and have the same timing as theprimary and/or secondary heads. Auxiliary headsor active or continuous “signals ahead” flasher signsshould be used whenever the traffic signal visibilitydistance of Table 24 cannot be obtained. The locationof the auxiliary heads themselves shall comply withthe visibility distance of Table 24 or the flasher signsmust be used.

The designer must be aware of the problems andcheck each design carefully to eliminate theseproblems or optimize the design to the give the bestpossible visibility.

Auxiliary Heads at Bridge Obstructions

Bridge obstructions are typically the easiest to designfor as accurate bridge details are always available.Where normal signal head visibility may be obstructedby a bridge underpass, low mounted auxiliary headsmay be required as indicated in Figure 16.

Auxiliary Heads at Geometric Curve Obstructions

Special considerations should be given to signalvisibility on horizontal roadway curvature where signalvisibility is normally available, but the traffic signalsare not conspicuous. This may be because themotorists are not looking far enough or are focusing

Figure 18 - Use of Continuous Flasher

PLAN

DISTANCE AS REQUIREDBY GEOMETRICS

LOWEST SIGHT LINE

B

A

A,B

200mm AMBERFLASHER BEACON (CONTINUOUS)

"SIGNALS AHEAD" SIGNSEE OTM

PROFILE

C



these effects. At these locations, a continuous singleflashing beacon with the oversized “Signals Ahead”sign (Wb-1102A) may be required as shown in Figure18.

The sign can be located at any reasonable distanceupstream from the signalized intersection beyond thevisibility distance shown in Table 24 and in generalconformance with signage guidelines of the OTM.

An active double flashing beacon (“bouncing ball”effect) with the oversized “Signals Ahead” sign (Wb-1102A) complete with the word tab “PREPARE TOSTOP WHEN FLASHING” (Wb-102At) may be requiredin the following circumstances:

• poor visibility and where location of anauxiliary head does not suit the installation;

• sight restrictions at the bottom of a hill orsteep downgrade;

• signal is the first one encountered by driversafter travelling a substantial distance on adivided highway where a signal may not beexpected.

An example of this situation is shown in Figure 19.Note that the sign flashers should be located and wouldoperate as described in Section 3.

Obstructions Due to Large Vehicles

Improper spacing between the primary and secondarysignal heads may cause loss or restriction of visibilityfor motorists travelling directly behind large vehicles,particularly where many trucks are turning left. Theminimum spacing of 5.0 m between primary andsecondary heads is meant to mitigate this effect tosome extent. It is not necessary to design for allcircumstances as long as several basic rules of signalhead spacing are followed. Where median islandsexist, some municipalities install auxiliary secondarysignal heads on the far left side of roads, at lowermounting heights, to mitigate the visibility impairmentcaused by large vehicles.

Figure 19 - Use of Active Flasher & Sign

Figure 20 - Optically Programmable Heads,Example in wide Median

Figure 21 - Optically Programable Heads,Example on Parallel Roads

OBSTRUCTION

DISTANCE AS PER

OPERATIONAL GUIDELINES

ALTERNATING 200mm AMBERFLASHERS (OPERATE ONCONTROLLER TIMING ONLY)

"SIGNALS AHEAD"SIGN SEE OTM

TABPREPARE TO STOP WHEN FLASHING

B

A

OPTICALLY PROGRAMMABLE HEADS FOR LTL MOVEMENT

NORMAL HEADS FORTHROUGH MOVEMENT

2

2

2

EXPRESSWAY

SERVICE ROADOPTICALLYPROGRAMMABLEHEADS

9A

9A



Optically Programmable Signal Heads

Skewed intersections with non-standard turning lanesmay require optically programmable signal heads toavoid confusion to motorists in adjacent lanes asindicated in Figure 20 (p.89). Similarly, signal headsbetween two separate parallel roadways may requirefocused lenses to prevent confusion on the non-controlled roadway as shown in Figure 21 (page 89).

Optically programmable signal heads may be usedfor displays at closely spaced intersections. Here, themotorist may focus on the furthest set of signals andmiss the closest set and the optically programmablesignal heads help to mitigate this problem.

5.6 Pole and Signal Head Locations

Primary Signal Head Locations

General

The primary signal heads are the most importantbecause they are most directly in the line of sight ofmotorists. The primary heads shall be located at thefar right corner of intersections. The primary headsshould be located in accordance with the followingguidelines:

• At a longitudinal distance from the approachstop line of 12 m minimum (with 15 m thepreferred minimum) to 55 m maximum asshown in Figure 22.

Figure 22 - Primary and Secondary Head Locations

10.0m MAX

PRIMARY POLE RANGE

3.0m MIN.

5.0m MAX.

PRIMARY HEADRANGE

VISUAL DIFFERENCEIN HEIGHT

PRIMARY HEAD LOCATION12m MIN.55m MAX.

15M

MA

X

5m M

IN.

0.5m

MIN

.

MID

LA

NE

FROM MID-CROSSWALKTO 10m FROM SECONDARY



The 15 m distance corresponds to a normal windshieldvisibility cutoff for a signal head mounted at 5.0 mheight and this distance may be reduced to 12 mminimum where tight conditions exist (with a lowermounting height used to ensure visibility if necessary):

• At a maximum longitudinal distance of 10 meither way from the median pole location, asmeasured along the centreline of theroadway, is recommended as shown in Figure23.

• If the above guidelines and standard mastarm lengths allow, the poles arerecommended to be as close to theintersection as practical to allow otherattachments such as secondary head mastarms and pedestrian equipment. If practical,the poles should be within 3.0 m of the centreof the crosswalks while taking aestheticrequirements, utility clearances and mast armlength restrictions into account. Iterative trialsof the design are normally required.

Figure 23 - Primary and Secondary Heads Without Islands

0.81.5

CROSSWALKMAX.

10 M

AX

.

10M

AX

.CL

CROSSWALKCL

5.0 MIN.15.0 MAX.

LANE MAX.

0.5 MIN.

CL

RANGE OF SECONDARY HEAD(PREFERRED OVER E/P)

FOR PROTECTED / PERMISSIVESIMULTANEOUS LEFT TURNOR LEFT TURN ARROWADVANCED GREEN

20.0

MA

X.

RANGE OF PRIMARYHEAD (PREFERREDOVER C LANE)L

15.0

MIN

.55

.0 M

AX

.



• A minimum lateral distance of 5.0 m and amaximum (desirable) lateral distance of 15.0m (22 m absolute maximum distance) isrequired between the primary and secondaryheads under normal conditions. Since thesecondary heads are normally located in theflare using the same rules as for primaryheads, trial mast arm lengths are usuallyrequired during design.

• A maximum longitudinal distance of 10 meither way from the primary pole location, asmeasured along the centreline of theroadway, should be obtained where possible.

• Secondary heads with left turn arrows shouldbe located as near to the intersection aspractical.

With Median Islands

Where median islands are present (with a minimumof two or more receiving lanes), primary andsecondary signal heads should not be too closetogether laterally nor too far apart longitudinally suchthat one head appears to be much higher than theother from the approaching motorist’s perspective.Figure 22 shows the range of the primary head whenthe secondary head location has already been set.The dimensions are shown between heads.

The primary head should also satisfy the cone of visionrequirements shown in Figure 14 for each approachlane. During design, it is important to plot the signalheads accurately on plan (usually a point at the endof the mast arm) and desirable to produce the finaldrawing in a similar manner so that visibility can bechecked.

Without Median Islands

Normally, opposing secondary heads are laterallyoutside (further from centreline) of the primary headsby a minimum of 1.0 m as shown on Figure 15. Thenormal location for the secondary heads in this caseis between 0.5 m and 0.8 m from the edge of

• The standard offset from the through edge ofpavement should be used. This offset is forsafety purposes and must be maintained at alltimes for King’s Highways. Where the polesare located within the turning flare area of thepavement, the offset may be reduced to 1.5m from the back of the curbs to allow astandard 1.5 m sidewalk width between thecurbs and the poles or 0.6 m absoluteminimum in curbed areas with operatingspeeds of 40 or 50 km/h. Refer toSubsection 5.3 for safety guidelines.

With Median Islands

For a straight 2-lane approach with a separate left-turn lane and a median island, it is normally desirableto mount the primary head at the 0.5 m minimumoverhang in the curb lane in order to get as muchlateral distance as practical between the primary andsecondary heads.

The primary and secondary heads should beseparated by a minimum of 5.0 m and a desirablemaximum of 15.0 m with an absolute maximum of22 m. The lower value allows for visibility blockageof one of the heads by larger vehicles while the uppervalue normally allows for at least one of the heads toremain within the 30o cone of vision at all times.

Without Median Islands

Where median islands are not used, it is desirable toposition signal heads between the 1/4 point and3/4 point of the curb lanes as shown in Figure 23. Inthis case, primary poles and heads are normallydesigned prior to the secondaries.

Secondary Signal Head And Pole Locations

General

Secondary heads, other than those in median islands,should be located using the following guidelines:



distances and visibility criteria are met. The secondaryheads can also be placed up to 1.5 m from the edgeof pavement if necessary to meet other criteria.

5.7 Pedestrian Signal Heads

Pedestrian Indications

Pedestrian indications shall consist of two symbols,the “lunar white” Walking Pedestrian (outline or solid)and the ”translucent orange” Hand Outline. Note thatthe Ontario and Canadian Standards are different fromthat of ITE Publication ST-217.

The symbols may be contained in a single minimum30 x 30cm (lens) housing or have separate housingsprovided, with the Hand Outline section mounteddirectly above or to the left of the Walking Pedestriansection, or in the case of a single lens, the symbolsmay be superimposed over each other or offset withthe hand outline on the left.

When illuminated, the pedestrian signals shall berecognizable from a distance of 30 m under normalconditions of visibility. The flashing Hand Outlineshould be used in all traffic control signals as aclearance interval and a warning to pedestrians thatthe walking time is terminating.

Guidelines For Pedestrian Signal HeadInstallation

It is recommended practice to install pedestrian trafficcontrol signals in most cases. Pedestrian traffic controlsignals are mandatory where it is necessary to controlthe sequence or length of pedestrian phasesindependent of vehicular phases or where it isnecessary to eliminate pedestrian confusion atapproaches containing traffic control signal heads witharrows. Where one or more of the pedestrian

crosswalks at an intersection justify pedestrian signals,it is usually desirable for uniformity and goodobservance to place pedestrian signals on allcrosswalks. A pedestrian must be able to walk to anycorner of an intersection. An exception to this occursat a ramp terminal where it is not usual practice tohave pedestrian crossings or pedestrian signals, forcrossing the through road, on the side of theintersection which receives left-turning traffic from theside road. This may also apply to any intersectionwhere it is desirable to ban particular pedestrianmovements due to large left-turn volumes. Suchrestrictions must be supported by proper signing asshown elsewhere in the OTM.

Pedestrian signal heads should be installed inconjunction with vehicular traffic control signals underany of the following conditions:

1. When a traffic signal is installed under thepedestrian justification.

2. When pedestrians and vehicles are movingduring the same phase and properly adjustedpedestrian clearance intervals are needed tominimize vehicle-pedestrian conflicts.

3. When an exclusive phase is provided or madeavailable for pedestrian movement in one ormore directions, all vehicles being stopped.

4. When heavy vehicular turning movementsrequire a semi-exclusive pedestrian phase forthe protection and convenience of thepedestrian.

5. When pedestrian movement on one side ofan intersection is permissible while trafficfrom only one approach is moving.

6. When an intersection is so large andcomplicated or a road so wide that vehicularsignals would not adequately servepedestrians.

pavement towards centreline. The second choice isdirectly over the edge of pavement provided that range



7. When the minimum green intervals forvehicles at intersections with traffic-actuatedcontrols is less than the minimum crossingtime for pedestrians and equipment isprovided which extends the green time uponpedestrian actuation (normally bypushbutton).

8. When complex phasing operation wouldtend to confuse pedestrians guided only bytraffic signal indications.

9. When traffic signal heads using arrows areused.

10. When pedestrians cross only part of theroad, to or from an island, during a particularphase.

11. When the traffic signal heads fall outside ofthe normal vision of pedestrians such as at“T” intersections, one-way streets or at largeintersections.

Guidelines For Pedestrian Pushbuttons

The use of pedestrian heads will require pedestrianpushbuttons at actuated traffic signals. Pedestrianpushbuttons should be located with the followingguidelines:

• The pushbuttons should be installed on the“through sidewalk” side of the pole;

• The pushbuttons should be in line with thecrosswalk and not perpendicular to thecrosswalk; location should be within 3.0 m ofthe edge of the crosswalk;

• It is desirable that a “push button for walksignal” sign be installed at each pushbutton.

Mounting Height And Location

Pedestrian heads shall be mounted at a minimum of2.75 m as measured from finished grade at the edgeof pavement to the bottom of the signal housing. Thisdimension should be used unless unusual

circumstances require a greater height but pedestrianheads shall not be mounted at the height of vehicleheads.

If practical, pedestrian heads should be mounteddirectly behind the sidewalk facing along thecrosswalk. Where necessary, the heads may bemounted within 3.0 m of the edge of the sidewalk inthe crosswalk-facing direction and within 1.5 m ofthe edge of the crosswalk laterally. A check shouldbe made that the pedestrian heads will not be hidden,from pedestrians on the other side of the roadway, byvehicles at the stop line.

5.8 Miscellaneous Traffic Control

Intersection Pedestrian Signals

Intersection Pedestrian Signals (IPS) may be installedat intersections which are characterized by very lighttraffic on the side road but have considerablepedestrian volumes. IPS require that a normalcrosswalk be pavement marked in accordance withstandardized practice for traffic signals and that theside road be provided with stop signs (if not alreadyprovided) as shown in Figure 24.

Figure 24 - Intersection Pedestrian Signals

15.0mMIN.

"STOP HERE ONRED SIGN"



Standard three-section signal heads are used for themain road, and pedestrian signals with pushbuttonsare required for the crossing.

Signal heads may be mounted on the same poles,either back-to-back, as shown in the example, orindependently.

One example of IPS is shown. It is possible to installthe crossing on the opposite side of the side road orto install dual crossings, one on each side. Details ofthe latter may be found in the TAC MUTCD.

Mid-block Pedestrian Signals

Where justified by continual disruption of traffic flowor by conditions of collision histories and heavypedestrian volumes and delays, vehicular andpedestrian traffic control systems may be installed atmid-block locations. All pavement marking featuresare similar to normal signalized intersections with thevehicle stop lines set back at a minimum of 12 m(15 m recommended practice) from the edges of thecrosswalks. Section 4 gives justification criteria forthe use of mid-block signals. Mid-block signals shouldbe used in lieu of PXOs where the posted speedexceeds 60km/h, where there are more than fourlanes or where other PXO criteria are not met.

Lane Direction Signals

Lane direction signals are normally used to changethe direction of traffic flow for single lanes, multiplelanes or the full roadway during various times of theday. The normal application is characterized by a veryheavy morning Peak Hourly Volume (PHV) in onedirection and a similar very heavy afternoon PHV in

the other direction. This characteristic is normally foundwhere alternate routes, such as other bridges acrossa river or other routes up or down a mountain, are notavailable or as convenient as the roadway in questionand therefore the classic tidal flow rush hour patternevolves.

Lane direction signals shall be suspended directly overthe approximate centre of the lane to which they apply.Signals for different lanes should be mounted at auniform height and so positioned that they form astraight line crossing the roadway at right angles. Eachsignal head must be mounted a minimum of 4.5 mover the pavement, with 5.0 m preferred.

Lane control signals must be carefully located inadvance of, or beyond, an intersection controlled bynormal traffic control signals so as to eliminatepossible confusion by the indications. A signalindication must always be illuminated in bothdirections of the lane or lanes controlled.

The signal indications consist of a red “X” and a greenarrow (downwards) as shown here. The layout of thelane direction signals should take visibility into accountas follows:

• At least one set of indications should bevisible to the motorist at all times;

• A 30 cm size lens is available and the size ofthe symbols relate to visibility up to 150 mcorresponding to use with operating speeds of60 km/h or less. Similarly, a 40 cm size lens isavailable which is visible up to 225 m andsuitable for use up to an operating speed of80 km/h;

• Spacing of the lane direction signals shouldbe practically set at a minimum of the limitsof visibility (approximately 150 m for 30 cmlenses and 225 m for 40 cm lenses); and

• Lane direction signals in tunnels may need tobe mounted elsewhere other than over thecentre of the lanes due to height restrictions.



Ramp Metering Signals

Heads for ramp metering are considered special foruse on freeway entrance ramps and are governed byRegulation 626 (5) of the HTA. The primary headmay be mounted at 2.75 m if not over traffic. Thesecondary head should be mounted at 1.0 to 1.2 m toprovide driver visibility since the stop line is directlybeside the secondary head.

Signals Near Railway Crossings

Where railway crossings actually lie within theintersections themselves, special treatment of railwayand highway signals shall be required to provide greaterprotection for vehicles. Examples of this are given inthe TAC MUTCD.

Where the railway crossings are in such close proximityto the intersections that back-ups from the vehiclesignals will undoubtedly occur, the interconnection ofrailway and vehicle signals will be required, for thepurpose of applying pre-emption to the vehicle signals,unless these back-ups can be eliminated by other meanssuch as the use of arrow indications which permitnon-conflicting movements. Pre-emptive signals mayalso be used to activate other devices such as blank-out signs for turn prohibition during train crossings.

Where the railway crossings are within 150 m of theproposed signal installations, an evaluation of probableback-ups from the signal systems shall be carried outby the road authority and submitted to the appropriaterailway owner for approval, coordination and costing.This evaluation shall estimate the times of day andprobable duration of any back-ups likely to obstructthe crossings.

Signals which require railway interconnection shouldnot be constructed until the approval of the railwayowner has been received and cost sharing has beenresolved.

Transit Priority Signals

Transit priority signal indications(TPSI) may be used to assign right-of-way to public transit vehicles overall other vehicular and pedestriantraf fic movements within anintersection. The signal indicationsallow for the movement of transitvehicles through signalizedintersections while all otherconflicting traf fic faces redindications. Transit priority signalsare generally used at intersectionsand may be operated exclusivelyduring protected transit movementsor concurrently with other non-conflicting vehicular movements.

Transit priority signal indications are specified in HTARegulation 626 (2), and are mounted directly abovethe red indications as shown. TPSIs consists of “lunarwhite” vertical bars on opaque backgrounds, of 20 or30 mm lenses sizes, and mounted on any type of signalheads up to 4-sections. TPSIs are generally used atintersections where there are dedicated transit lanes orwhere their use would improve the efficiency of thetransit routes and the safety of the intersections.

Some design guidelines are as follows:

• TPSIs may be provided with bus detection;

• TPSIs may be installed on exclusive signalheads which face transit traffic within aroadway corridor;

• TPSIs may be used with caution atintersections with mixed use traffic and onlywhen a transit vehicle is first in queue or if apriority phase which clears queued vehiclesprecedes the TPSI phase, otherwise there maybe the potential for motorist confusion ininterpretation of the transit priority signals;



• TPSI placement is flexible and they may beused on signal heads which are not directlyopposite transit lanes, on transit-only left turnsignal heads and so on; and

• For safety reasons, the jurisdiction shouldcarry out an extensive public awareness andeducation plan prior to implementation oftransit priority signals.

Movable Span Bridge Signals

When roadways cross drawbridges, swing bridges orlift bridges, normal traffic signal heads should beconsidered in conjunction with control gates or otherforms of physical protection.

A great deal of care should be taken with the designof bridge signals as it is not possible to stop largewater vessels in a short distance and, onceactivated, the bridge mechanism normally has tocontinue to open the bridge. It is good practice toallow a significant distance or 15 m minimumbetween the end of the movable part of the bridgeand any barrier protection as a place to park one ortwo vehicles in an emergency.

Portable Lane Control Signals

Portable Lane Control signal systems consist of single“standard” vehicle traffic signal heads, normallymounted on movable poles at a minimum height of2.75 m from the roadway surface to the bottom ofthe heads. These signals are sometimes used toreduce traffic flow to a single lane in alternatedirections at very local work areas on the roadwaywhich required lane closure. Use of portable signalsare an alternative to continuous flagging by flagpersons, and are not to be confused with temporarytraffic signals.

It is recommended practice that the use of portablelane control signals shall only be allowed where theposted speed is 60 km/h or less, where full illuminationexists if the closure continues at night,

where driveways and intersections are not included inthe closure area and where the lane closure will becontinually attended.

Portable Lane Control signals must be installed inaccordance with the requirements of Regulation 606of the HTA which covers the physical and signagerequirements.

Signals With Audible Indications

Audible indications may be used to assist pedestrianswho are visually disabled. Audible indications are notcovered in the HTA. The designer is referred to thetreatments given in the TAC MUTCD.

Tunnel Signals

“Tunnel Signals” are composed of two types:

• signals at the ends of a tunnel which are usedto prohibit the entrance of traffic in the case ofa mishap within the tunnel;

• lane control signals within the tunnel, and onthe tunnel approaches, used for reversible lanesor for the closure of lanes for maintenance.

Bicycle Control Signals

This space is reserved for future addition of therequirements of bicycle control signals.



5.9 Detection

General

Vehicle detection devices are used to indicate the needfor a call or extension of green time by passage ofvehicles over a specific point on the roadway. Vehicledetection devices are also used to indicate thatvehicles are present and waiting for signal indicationsto change and to indicate that vehicles are in linebehind other vehicles waiting for signal indicationsto change (left turn “setback” loops). In areas postedat speeds of less than 80 km/h, there is greaterconcentration on maximizing intersection efficiencythan on dilemma zone protection. Special detectortypes or special layouts can also be used to detectbuses only for bus priority signal actuation.

The dilemma zone is the area approaching the stopline in which the motorist, on the start of amber, willbe momentarily undecided as to whether to stop orcontinue through the intersection, therebyencountering a dilemma.

At critical intersections, detection zone lengths andgap settings are normally designed to terminate greenwhen headways are greater than two to three seconds.

Pedestrian pushbuttons and pre-emption devices arealso forms of detection and are discussed in Section3.

The current practice of many authorities uses loopsinstalled in the pavement together with detectoramplifier/sensor units installed in the controller cabinets asdetection devices. Other types of detection are available andare continually being developed. For the purposes of thissection, detector design will be described using loops,recognizing that if alternate forms of detectors are used, theroad authority should ensure that the operational features aresimilar to loops for the application.

The location and correct positioning of detectiondevices is of the utmost importance if actuated controlis to be effective. Good design requires that objects

affecting detector performance be taken into account.This includes parked vehicles, manhole covers, transitstops, service stations or other facilities with busyentrances, and so on.

System loops may be square or diamond shaped loopsinstalled in each lane. For a central computer system,loops are placed only on strategic arterials and ineither inbound (towards the central business district)or outbound lanes. The traffic volumes, speeds andvolume/densities on only a few sets of loops maythen be used in software algorithms to select timingand phasing plans. For systems such as the SplitCycle Offset Optimization Technique (SCOOT), dualsets of system loops are placed in each lane well inadvance of each intersection so that the optimal cyclelength and offset timing may be calculated andtransmitted to the next intersection.

Presence Loop Detectors

Presence loops are used to detect the presence, orcontinued occupancy, of vehicles, provide calls to thecontrollers or extend green times for vehicles. Theycan be installed at or near the stop lines at intersectionapproaches or as “setback” loops in turning lanes todetect if there are two or more vehicles waiting toturn.

Presence loops may be of rectangular or irregularshapes, they may be lane selective (installed asseparate loops in each lane) or all inclusive (installedas one loop across several lanes) and they may beused with a user settable time delay (1 to 15 seconds)feature to allow vehicles to stop, pause and continuewithout registering a call (as in right-turn lanes).

The recommended placement of presence loopsrequires maximum setbacks of 4.5 m from theintersecting through edge of pavement and a coveragearea behind the stop lines of 12 m in length for postedspeeds of 80 km/h and above and 5.0 m minimumotherwise, as indicated in Figure 25.



Long Distance Loop Detectors

Long distance passage loops are normally used atintersections to provide either actuation of signalphases or to provide extended green times for vehiclespassing through the dilemma zone. When used in theformer case, they are sometimes referred to as “triploops”. When used in the latter case, they are sometimesreferred to as “extension loops”.

As a recommended practice, these loops should beused as extension loops to extend green time on themain road for roadways of posted speed of 80 km/hor more and it is also good practice to use them atlesser speeds. The loops are normally installed per laneand are of 1.8 x 1.8 m square configuration or the

Figure 25 - Presence Loops

Figure 26 - Extension Loops



equivalent diamond shaped loops (preferred) as shownin Figure 26 (page 99).

The advantages of use are to serve higher speed trafficso that vehicles receive an extended green indicationup to a maximum green time interval where max outoccurs (LOS D & E) or gap out occurs (LOS C or better).Vehicles approaching the signal will pass over thelong distance loops and extend the green time toensure that they are able to get within a one secondtravel time of the stop line before the start of theamber interval. The extension of green time allowsan approaching vehicle to pass through the dilemmazone. The distance from the stop line to the extensionloops is based on the time of entry of the dilemmazone as shown in Table 26.

Passage loops may also be used as calling loops inthe case of full actuation. In this case, a loop isinstalled in every intersection approach lane (or asingle loop across multiple lanes) at a distanceconsistent with those shown in Table 26. Each trafficapproach thereby has the ability to place a call for anapproaching vehicle, with sufficient time to change

the signal indication to green before vehicles have toslow to a stop. In full actuation, another set of loopsmay be placed near the stop line so that vehiclesarriving at the end of the maximum green time, andforced to stop, do not get trapped without any form ofactuation (alternatively, recall to a minimum green timewill clear the queue). This type of operation shouldnot be used on high speed roads as it encourageslocal motorists to anticipate the green signal and maycause collisions with side road traffic entering onamber/all red.

The design of loop details with the various types ofloops such as simple, duplex (quadrapole TM),powerhead, preformed, etc. and with alternatedetection devices is beyond the scope of this manual.Reference for further details should be made to theMinistry’s Electrical Engineering Manual2.

5.10 Layout Design

General

The general requirements of Subsection 5.3 should beclosely followed when laying out primary andsecondary head and pole locations. This section usesseveral example intersections to illustrate the variousrequirements.

Crosswalks And Sidewalks

General

This section gives an overview of the designprocedures required to produce the signal andcrosswalk/sidewalk designs related to the overalltraffic signal design.

The material in this section should be treated as thefirst step in a detailed design.

Table 26 - Distances from Stop Line for LongDistance Loops

* edge of zone as determined by perception and reaction time plusbraking deceleration time to within 1 second of the stop line.

** based on 5 seconds total time to within 1 second of the stop lineallowing for average motorist time for perception, reactionand braking time.

60

70

80

90

100

70

90

110

125

140

85

100

115

125

140

OperatingSpeed (85th

percentile)

Distance fromStop Line (m)

(based on Edge ofcemma zone)*

Distance fromStop Line (m)

(based on 5 second

line)**



Design of Crosswalks and Sidewalks

1. Coordinating Crosswalk Locations

Inappropriate designs of crosswalks and sidewalks cansignificantly hinder the design of a set of traffic controlsignals. It is the responsibility of the signal designerto ensure that any changes to the preliminary designare compensated for by appropriate changes to thedesign of crosswalks and sidewalks.

Crosswalk locations are critical to pedestrian signaland pushbutton locations . For new roadwayconstruction or reconstruction, the design of thecrosswalks must be coordinated between the roaddesigners (sidewalks and dropped curbs are affected)and the traffic signal designers (pedestrian signalfacilities are affected).

Sidewalk locations which are designed at the propertyline and leave a large boulevard between the back ofcurb and the sidewalk are unacceptable at signalizedintersections since pedestrians must have access topushbuttons and must cross properly at crosswalks.The sidewalk design should be locally adjusted to meetthese conditions as shown in Figure 27.

Some basic guidelines to the layout of crosswalks andsidewalks are given here since the layout design ofpedestrian signals and pushbuttons must beintegrated with these items and the signal designermust be able to discuss and support his/her casewith the other offices involved.

2. Crosswalks

The design of pedestrian crosswalks is not a fixedscience and is subject to opinions and preferences.The examples given here are representative of systemsin use.

Figure 28 - Crosswalk Design

Figure 27 - Crosswalk and Sidewalk Locations

PREFERRED CROSSWALK LOCATION

R.O.W. UNDESIREABLE SIDEWALK LOCATION(VEHICLES INTERFERE)

PREFERRED SIDEWALK LOCATION(ADJACENT TO POLE)

DESIRABLECONDITION

DROPPED CURB

ACCEPTABLECONDITION

2.0m MIN.

1.0m MIN.2.5m MIN.

500mm MIN.



Figure 28 (page 101) shows a typical intersection onwhich one side is standard and the other side ismodified. The crosswalks are laid out with thefollowing guidelines in mind:

• the minimum crosswalk width is 2.5 m. Thedesirable minimum crosswalk width is 3.0 m.The width may be increased to match widersidewalks in downtown areas or allow greatertwo-way pedestrian volumes;

• the outer edge of the crosswalk is normally1.0 m from the edge of the stop line. Thestop line location can vary if necessary fromthe standard location which starts at the endof the island;

• the inner edge of the crosswalk should be aminimum of 500 mm from the through edgeof pavement of the parallel roadway forroadways posted under 80 km/h and 1.0 to1.5 m for roadways posted at 80 km/h andabove;

• it is preferred to have each crosswalk reachthe far curb without intersecting with theother crosswalk across the other roadway.This directs pedestrians to the far sidewalk toawait the other pedestrian signal instead ofwaiting near the curb in the pavement area;

• where the geometry is difficult and thecrosswalks tend to intersect in the turningflare, it is better to have the inner edgesintersect at the curb than to carry each set oflines through each other;

• it is preferred that crosswalks be made to lineup with proposed sidewalks or droppedcurbs. The final design of the sidewalks andcurbs should integrate with that of thecrosswalks;

• where existing geometry is used, the edgesof crosswalks should line up with existingpoles to improve pedestrian signal headvisibility and pushbutton accessibility;

• crosswalks should not cross over the centremedian island on roadways with postedspeeds of 80 km/h and more and should notcross over any median not equipped withwheelchair ramps or at-grade depressions;

• consideration should be given to snow-covered roadways where crosswalk lines maynot be visible. In these cases, and wherepossible, the crosswalk lines should be withinthe most direct route from sidewalk tosidewalk; and

• crosswalks should be as short as possiblewithout compromising other design factors.

3. Sidewalks

The sidewalk and dropped curb designs should becoordinated with the road designer after crosswalksand all other equipment have been designed. Wherethe road authority allows options to sidewalk locations,a plan of the desired sidewalk locations, using thesignal design plan as a base, helps to discuss therequirements. The following should be considered:

• the sidewalk approaches to the curb shouldfall within the edges of the crosswalks, not onthe stop line, etc.;

• where possible, the pole footings (at least inpushbutton locations) should be adjacent toand flush with sidewalks or hard surfaces(sidewalk extension, asphalt, etc.) should beplaced between the sidewalks and the poles;

• where concrete or asphaltic concrete sidewalksare not available, a hard surface such asasphalt should be considered to be placedbetween the pedestrian pushbutton and otherhard surfaces.

4. Integrated Design

Care in layout of the crosswalk markings can improvethe appearance and operation of the intersection forpedestrians. Note that the dropped curbs and droppedsidewalk ramps for disabled persons at each crosswalkare shown on the roadway plans and must match the



final pavement marking. Where sections of droppedcurbs are separate but close together, they sometimesleave a very short length of raised curb, making thesidewalk ramps abrupt and sometimes difficult to walkon. The crosswalks in this case should be separatedsufficiently to allow a 2.0 m (desirable top-to-topdistance) length of raised curb as shown in Figure 28(page 101) or should be brought together with theinner lines meeting to eliminate the curb “bump”. Itshould be noted that the “bump” does serve thefunctions of providing guidance for visually impairedpedestrians and deters motorists from mounting thecurb.

Coordination of the final marking must be coordinatedwith the road designers to suit pedestrian pushbuttonand pedestrian head locations. Note that it issometimes necessary to revise median island designsto suit desirable crosswalk schemes provided that thetruck turning radii are accommodated.

5. Large Radii

Very large truck turning radii leave a large area of flaredpavement. This has the effect of significantlyincreasing the pedestrian walk time and of increasingthe difficulty of signal design due to the restriction inpractical single member arm lengths. The possibilitiesof installing a channelization island as shown in Figure29 may be investigated and discussed with the roaddesigners.

The island removes the turning traffic from theintersection and offers a pedestrian refuge area plusa good place to install a traffic signal. Caution shouldbe used however because of the safety concernsabout pedestrians crossing to the island as the legalresponsibilities of motorists and pedestrians on theramp are unclear as the ramp does not form part ofthe intersection. For channelized right turn lanes onroadways with posted speeds of 80 km/h and over,crosswalk markings must not be applied on the ramp.

For posted speeds of 80 km/hand greater, theminimum island size should be restricted to 10 mminimum on any one side and should be large enoughto obtain a minimum of 3.0 m offset to the pole fromany side. For posted speeds less than 80 km/h, theminimum island size should be restricted to 3.7 mminimum on any one side and should be large enoughto obtain a minimum of 1.5 m offset to the pole fromany side (a 3.0 m offset is still preferred if attainable).From an operational perspective for roadways postedat 80 km/h or greater, a full right-turn lane withadequate storage to remove all right-turning vehiclesfrom the signal operation is required as well as a fullacceleration lane for proper and safe merging on theside road.

Figure 29 - Use of Right-Turn Island

EDGE OF PAVEMENT WITHISLAND AND ADDITIONAL LANES

POLE LOCATIONS WITH LARGE RADIUS

POLE LOCATION WITH ISLAND

NORMAL EDGE OF PAVEMENT



5.11 Utilities

General

The designer must take great care to understand andcapture the temporary and final location of utilitiesthat will be on site during the traf fic signalconstruction. The final locations may include existingutility locations (where relocations are not requiredfor roadway purposes), relocated utilities orcombinations of both (as is normally the case ifroadway construction is involved). Time can be wastedif a designer assumes that utilities marked up from afield visit to the site are to remain in place throughoutconstruction. Note that most intersectionreconstruction projects widen the pavement andhence most pole lines require relocation and will notbe in the same location at the time of construction.

The road authority’s utilities coordinator is responsiblefor arranging for the location, financing and timing ofutility relocations. The basic co-ordination is normallycarried out shortly after grading cross-sections areavailable. This practice sometimes leaves little timefor the designer to co-ordinate the traffic signal work.

The designer must review the final locations of allutilities, with special emphasis on overhead highvoltage lines. In some cases, it will be necessary tore-open negotiations and arrange for mutuallyacceptable pole locations or power line heights. Manyutilities have a right to be present on the right-of-wayunder the Public Utilities Act (this provision applies tohydro, telephone, sewerage and watermain works anddoes not normally apply to natural gas or cabletelevision). Other utilities which are owned by theroad authority, for example fibre optic cable, shouldalso be checked. The utilities must co-operate to finda location satisfactory to the roadway authority. Inmost situations, locations can be found which aresatisfactory to both the utility and the road authorityand in many of these instances the signal design mustbe adapted from the standard to a compromise design.

Guidelines

The designer should be aware that some undergroundutility plans can be less than acceptable and shouldnot be relied upon with great accuracy. Many utilityplans are provided which have not been updated to“As Constructed” status. Utility stake-outs are usuallyonly reliable to within 1 m +. With theseapproximations in mind, the designer may choose oneof the following methods in designing equipmentlocations:

• Arrange for spot excavations and a survey ofthe exposed utility which can be plotted onplan. This would normally be required forlarge and important utilities such asunderground high voltage cables, fibre opticcables and high pressure gas lines. Wherethe exact location is known, signal equipmentmay be designed for 0.5 m clearance;

• Allow for 1.0 m minimum clearance betweenthe utilities (including infrastructure such asstorm sewers, sanitary sewers, watermainsand culverts) and the traffic signal equipment.Note that “clearance” is to the side of theequipment, not the centreline.

High voltage lines (over 750 V) require a minimumclearance of 3.0 m for local distribution lines up to44 kV and larger clearances for higher voltages inaccordance with the requirements of CSA StandardC22.3 No. I M. Note that these regulations areenforced in law under the Occupational Health andSafety Act. For transmission lines Ontario Hydro mustbe notified. Hydro authorities can normally beemployed to protect signal workers and equipmentfrom high voltage lines during installation of trafficsignals if it is necessary to come within the clearancezone.

The designer should inquire as to the voltage presentand be prepared to design the traffic signals to meetor exceed the clearance requirements, or have theelectrical utility carry out suitable relocations, withoutexception.



The following guidelines are suggested:

• where possible, plan layout should be doneby allowing a minimum of 5.0 m betweenhorizontal centres of electrical pole lines andtraffic signal poles. Where distributioncrossarm construction exists or is planned, theclearance should be increased accordinglybeyond that used for the normal standoff typeinsulators;

• as much clearance as possible is definitely adesirable feature as poles hit by vehicles can“cartwheel”, sending the signal mast arm intohigh voltage cables and causing majordamage. Good practice suggests that thetraffic signal poles should be at least 5.0 mfrom the overhead lines (as measuredhorizontally) or the power lines relocationshould be coordinated so as to be closer tothe edge of pavement locally and the signalequipment mounted on the utility pole. Indifficult situations, it may be possible tonegotiate for an increase in the utility poleand line heights to clear the signal equipment.Note that these criteria are somewhat idealisticand difficult to achieve in practice withincongested right-of-ways;

• where lighting is required, efforts should bemade to use the electrical utility poles ifadequate luminaire mounting height can benegotiated. The probability of a 10.5 mcombination signal and lighting pole fallingon the overhead lines is much higher thanthat of a 7.5 m signal pole.

Overhead low voltage lines, with the exception of theelectrical neutral, are insulated and a minimumclearance of 300 mm is required to prevent rubbingof the insulation. In negotiating with the electricalutility, it is desirable to try and get the neutral and anylow voltage cables raised locally from the normal8.0 m above grade to 9.5m above grade (one polelength increment of 1.5 m) such that the neutral andlow voltage cable locations are well above the tops of7.5 m signal poles and such that a lighting bracketattachment height of 10.3 m can be obtained.

There is no requirement to maintain other than theminimal clearance of 150 mm to either telephone orcable television lines. Efforts must be made however,to arrange to have these raised if the cables will visuallyobstruct the traffic signal heads.

5.12 Layout Practice

General

In the drawings, the “Normal” layout indicated is for anapproach with Highway type heads and possiblyadvanced green arrow heads.

Guidelines By Example

The following figures are shown:

Figure 30 “T” Intersection Approach;Figure 31 Approach Without Median Island

(Normal or Advanced Green);Figure 32 Approach Without Median Island

(Fully Protected Left Turns);Figure 33 Approach With Median Island

(Normal, Advanced Green orSimultaneous Protected/Permissive Lefts);

Figure 34 Approach With Median Island(Fully Protected Left Turns);

Figure 35 Approach With Wide Median(Fully Protected Left Turns);

Figure 36 Approach With Double Lane LTL(Fully Protected Left Turns);

Figure 37 Ramp Terminal Opposite Free-flowRamp;

Figure 38 Short Offset Intersection;Figure 39 Long Offset Intersection;Figure 40 Pedestrian Signal poles.



“T” Intersection Approach

A typical “T” intersection with two-way traffic on theside road is shown in Figure 30. Note the following:

• normal Highway heads may be used;

• the primary and secondary poles shouldpreferably be located clear of the edge of theprojected through lane for safety purposesusing 3.0 m clearance as a desirable setbackfor roadways posted at 80 km/h and overand using 1.5 m minimum for roadwaysposted at under 80 km/h;

• where a double lane left or right turn isallowed, they should not occursimultaneously with conflicting pedestriancrossings; and

• where turning volumes and pedestrianvolumes allow, recommended practice is thatonly one crosswalk should be used. Thecrosswalk should be located on the approachwhere there will be no interference withpedestrians from left-turning traffic.

Approach Without Median Island (Normal OrAdvanced Green)

A typical simple approach, without a median islandand with normal or advanced green indications, isshown in Figure 31. Note the following:

• there is no median pole and therefore theprimary head should be at or close to thecentre of the lane;

Figure 30 - “T” Intersection Approach

RANGE OFSECONDARYHEAD

AREA OF EXTENDED EDGES OFPAVEMENT TO BE FREE OF POLESIF POSSIBLE

15.0

m M

IN.

55.0

m M

AX

.

5.0m MIN.

15.0m DESIRABLE MAX.22m ABSOLUTE MAX.

0.5m MIN.

LANE MAX.CL



• if mast arm lengths allow, the poles should bewithin 3.0 m of the crosswalk to enablepushbutton and pedestrian head installationon the same poles.

Approach Without Median Island (Fully ProtectedLeft Turns)

A single lane left-turn approach, without a medianisland and with fully protected left-turn indications, isshown in Figure 32 (page 108). Note the following:

• this is a non-typical application using aerialinstallation of the left-turn (type 2) headsbecause of the requirements for siting theprimary left-turn head within the projectedleft-turn lane;

• this application is normally used only as aninterim measure until the intersection can bereconstructed with islands.

Approach With Median Island (Normal, AdvancedGreen Or Simultaneous Protected/PermissiveLefts)

Two approaches are indicated on Figure 33 (page 109);the northbound approach is “normal” with Highwayheads and the southbound approach is the often usedprotected/permissive one using the type 8, 8A, 9 or9A signal head in the median. Note the following:

Figure 31 - Layout at Approach Without Median Island

0.81.5

CROSSWALKMAX.

10 M

AX

.

10M

AX

.

CL

CROSSWALKCL

15m DESIRABLE MAX.22m ABSOLUTE MAX. MIN.

LANE MAX.

0.5 MIN.

CL

RANGE OF SECONDARY HEAD(PREFERRED OVER E/P)

FOR PROTECTED / PERMISSIVESIMULTANEOUS LEFT TURNOR LEFT TURN ARROWADVANCED GREEN

20.0

MA

X.

RANGE OF PRIMARYHEAD ( PREFERREDOVER 1/2 TO 3/4POINT OF LANE )

15.0

MIN

.55

.0 M

AX

.



• for recommended practice, the median(secondary) head is roughly over the edge ofthrough pavement. Standard mast armslengths “S” depend on the narrow medianwidth “W”;

• the combination used does not allow for aprotected north to west left turn.Simultaneous protected/permissive left turnsare possible only where both medianindications are type 8, 8A, 9 or 9A.

Approach With Median Island (Fully Protected LeftTurns)

A single lane left-turn approach, with a median islandand with fully protected left turn indications is shownin Figure 34 (page 109). Note the following:

• the left-turn primary head is to be locatedonly within the projected edges of the left-turn lane;

• the practical mast arm length “S” of theprimary left-turn head depends on the narrowmedian width “W” and is normally 1.2 m;

Figure 32 - Approach With Fully Protected Left Turn Heads and Without Median Island

PREFERRED LOCATIONS

AERIAL INSTALLATION1.5m MAX.

15.0

m M

IN.

55.0

m M

AX

.

CL CLCLLANE LANE

3.5m MIN.5.0m MAX.

5.0m MIN.

LTL

2 2

20.0

m M

AX

.



• the primary left-turn head must be separatedfrom the secondary through movement headby at least 2.4 m; the secondary throughmovement head must be separated from theprimary through movement head by thenormal rules of 5.0 m minimum and 15.0 mmaximum.

Approach With Wide Median (Fully ProtectedLeft Turns)

Figure 35 (page 110) shows a fully protected left turnlayout for a wide median of between 2.0 m and 15.0m width. Note the following:

• the left-turn primary head, type 2, is to belocated within the projection of the edge ofpavement of the left-turn lane (LTL) and apoint not more than the apparent end ofmedian island as shown;

• a minimum separation of 3.0 m should beobtained between the LTL primary head andthe through secondary head;

• the LTL secondary head should be over theedge of pavement by 0.8 m (preferred) andangled towards the LTL at the stop line orslightly upstream;

• where the median width exceeds 15 m,two sets of separate signals are requiredin accordance with Section 144 (2) of theHTA.

Approach With Double Left Lane (Fully ProtectedLeft Turns)

Figure 36 (page 111) shows a fully protected left-turnapproach for a dual left-turn lane. Note the following:

Figure 34 - Fully Protected Left Turn ApproachFigure 33 - Normal or Protected/Permissive Layout

9PROTECTED / PERMISSIVESIMULTANEOUS LEFT TURNLAYOUT OR ADVANCEDGREEN ARROW SAME RULESAS NORMAL LAYOUT

S = 0.6 FOR W < 2.0mS = 1.2 FOR W > 2.0m

NORMAL LAYOUT

CROSSWALK CL

15.0

m M

IN.

55.0

m M

AX

.

20.0

m M

AX

.

5.0 MIN.15.0m MAX.

S

3.0m

MIN

.5.

0m M

AX

.

10.0

m M

AX

.

RANGE OF PRIMARYHEAD LOCATION

0.5m MIN.

CL LANE MAX.

W

CL

W

CL

5.0 MIN.15.0m MAX.

S

W

LTL PRIMARY ONLY TOBE LOCATED WITHINTHESE LIMITS

0.5

S = 0.6 FOR W < 2.0mS = 1.2 FOR W > 2.0m

RANGE OF SECONDARYLTL HEAD (DESIRABLELOCATION IS EDGE OFPAVEMENT)

SEE RULES FOR"NORMAL LAYOUT"

CROSSWALK

10.0

m M

AX

.

1.50.8

5.0 MIN.15.0m MAX.

2.4MIN.

1.8m MIN.

10.0

m M

AX

.

2

2



• the mast arm length “S” for the LTL primaryhead depends on the median width “W” suchthat the distance between the LTL primaryand the through secondary heads is 2.4 m;

• the LTL secondary head should be over theedge of pavement by 0.8 m (preferred) andangled towards the LTL at the stop line orslightly upstream;

• the dual left-turn lane may require pavementmarked “tracking” lanes for guidance ofturning vehicles. Where a dual left-turn lanefaces a simultaneous dual left from the otherdirection, there must be sufficient room toseparate the outer tracking marks by at least3.0 m for safety purposes.

Figure 35 - Fully Protected Left Turn at Wide Median Approach

CROSSWALK CL

RANGE OF SECONDARY LTL HEAD

DESIREABLE LOCATION IS 0.8m TOTHE RIGHT OF EDGE OF PAVEMENT

1.5 0.8

3.0m

1.5 0.8

RANGE OF THROUGHSECONDARY HEAD

5.0m MIN.15.0m MAX.

5.0m MIN.15.0m MAX.

3.0mMIN.

LTL PRIMARY ONLY TOBE LOCATED WITHIN

THESE LIMITS

0.5

1.2 1.8

MIN. MIN.

10.0

MA

X.

10.0

MA

X.

2

2SEE RULES FOR"NORMAL LAYOUT"



Ramp Terminal

Figure 37 (page 112) shows a full layout for a freewayramp terminal on a free-flow exit ramp to an arterial.Note the following:

• the area for the ramp primary and secondaryheads should preferably be kept free of polesbetween the extended edges of pavement ofthe ramp;

• normal Highway heads may be used on thearterial provided that proper restrictivesignage is also used;

• where turning volumes and pedestrianvolumes allow, only one crosswalk should beused and should be designed on theapproach where left-turning traffic from theramp will not be interfered with;

• where a double lane left or right turn isallowed, they should not occur simultaneouslywith conflicting pedestrian crossings; and

• the through lane primary and secondary headson the arterial should be type to indicate thatno turns are to be made;

• the arterial secondary heads on medianmounted poles require side mounted mastarms of at least 0.6 m length since the islandsare in direct alignment and near median polesmay obscure front mounted heads.

Short Offset Intersection

Figure 38 (page 113) shows a typical layout for a “shortoffset intersection” where one side road is offset fromthe other. The configuration shown has been termed a“far right” offset since the side road on the right ofeither approach is farthest from the motorist. A “nearright” intersection is the opposite with the side roadon the right being nearest the approaching traffic.

In either situation, it is difficult to improve safety, wheninstalling traffic signals in lieu of stop signs, withoutseverely affecting the operation of the intersection.Note the following:

• the distance between the side roads can betreated similarly to a wide median. Themedian width of 15 m maximum for a singleset of signals can be applied;

• pedestrian crossings in the middle, betweenthe side roads, are not desirable with normalphasing. The side road approaches are servedon separate phases, allowing pedestriancrossings in the middle during one of thesephases and thereby providing an operationeffectively the same as at a T-intersection. Ifpedestrian crossings are then prohibited on theother approach, the phase for “no-crossings”approach can be kept to a minimum, and thecycle length as low as possible;

Figure 36 - Fully Protected Dual LTL Approach

SEE RULE FOR"NORMAL LAYOUT"

S1 = 1.8m MIN.S2 = 0.6m FOR W < 2.0mS3 = 1.2m MIN. FOR W > 2.0m

RANGE OF SECONDARYLTL HEAD

DESIREABLE LOCATIONIS 0.8m RIGHT OFEDGE OF PAVEMENT

CROSSWALK CL

1.5 0.81

0.0

MA

X.

2

W

5.0 MIN.

15.0 MAX

LTL PRIMARY ONLY TOBE LOCATED WITHIN

THESE LIMITS

2

5.0 MIN.15.0 MAX.

2.4

S2 S1

0.5

"TRACKING"PAVEMENT MARKING



• for visibility purposes, the distance from stoplines to a primary head is limited to 55 mmaximum; if more, the intersection is a “longoffset intersection”;

• pavement marking “tracking lines” are requiredto reduce motorist confusion. In theseintersections, once motorists have turned leftfrom the side road, it is difficult for them todistinguish between opposing through trafficand traffic which is turning left from the otherside road; and

• when a vehicle turns left from each side road,those motorists are confronted by a red lighton the arterial and confusion as to whether tostop or not will occur. Advisory signage doesnot appear to solve this problem.

The designer is directed to Metropolitan Toronto’s paper“Traffic Signal Control at Offset Intersections” 23 for a morethorough treatment of the subject.

Long Offset Intersection

Figure 39 shows a typical layout for a “long offsetintersection” where one side road is offset from theother, but not so much as to visually delineate entirelyindependent intersections to approaching motorists.These types of intersections may be divided into “farright” (as shown) and “near right” where the first sideroad on the right is the closest to the approachingtraffic. The design of traffic control signals at this typeof intersection is always a problem due to the confusioncaused by two sets of nearby signals facing motorists.Note the following:

Figure 37 - Ramp Terminal Intersection Approach

SEE RULES FORNORMAL LAYOUT

NOTE: CROSSWALKSNOT NORMALLY APPLIEDHERE (PEDESTRIANSIMPEDE LEFT-TURNINGTRAFFIC)

PROJECTEDEDGE OFLANE

SEE RULESFOR NORMALLAYOUT

MEDIAN POLETO BE OUTSIDEOF THE PROJECTEDEDGE OF LANE

AREA OF PROJECTEDEDGES OF PAVEMENTTO BE FREE OFPOLES.

1.8 MIN.1

1

5.5 MIN.15.0 MAX.

1

1

CL

CLLANE

0.5 MIN.LANE MAX.

6 6



• pedestrian crossings in the middle, betweenthe side roads, are not desirable unless phasingtimes permit the holding of turning trafficwhile pedestrians cross;

• the maximum viewing distance of 55 m forthe primary head from the stop line cannot beobtained as for the short offset intersectionand therefore independent sets of signals arerequired;

• the distance “D” should be as long as possible(15 m minimum is suggested) toaccommodate storage of trapped vehicles;

• if the distances to the next intersections permitsome variation in the timing without seriousdisturbance to the system, detection could beadded in the lanes between intersections toeither extend the green or let the next phaseactivate;

• past solutions to the visibility and confusionproblem include the use of opticallyprogrammable signal heads on the far set ofheads to attempt to hide them from viewfrom the far intersection, combined withsignal timing that provides the amberindication for the upstream traffic prior to theamber for the traffic between the offset legsat the intersection;

Figure 38 - Short Offset Intersection

Figure 39 - Long Offset Intersection

PAVEMENT MARKINGTRACKING LINES

15m MAX.

55m MAX.

55m MAX.

D



• a subtle but partially effective solution tomitigate motorist confusion consists ofpainting the far set of signal head housings adifferent colour than that of the near side;black faces on the far set and yellow faces onthe near set including the backs of housingsand of backboards that the motorists arefacing;

• where “D” is less than approximately 200 m, itis difficult to have the intersections operatingindependently or on a system without somesacrifices in timing, phasing and efficiency.Refer to Metropolitan Toronto’s paper “TrafficSignal Control at Offset Intersections”23 for amore thorough discussion of problems andsolutions.

Figure 40 - Layout of Poles With Pushbuttons

Layout Of Pedestrian Heads And Poles

General

In order to be effective, pedestrian heads must be easilynoticed by pedestrians . This requires somestandardization of locations with respect to pedestrianexpectations and with respect to crosswalks andsidewalks. Where pushbuttons are used, they mustbe accessible and convenient to the crosswalk beingserved.

Poles With Pushbuttons

Poles carrying pedestrian pushbuttons should belocated in accordance with the following guidelines:

SW

6.0m DESIRABLE POLE SEPARATIONMAY BE COMPROMISED. IT IS NOTDESIRABLE TO LOCATE THE PED.POLE BEYOND THE OUTERCROSSWALK LINE NOR DESIRABLETO LOCATE THE PRIMARY POLE BEYONDTHE NORMAL R.O.W. LIMIT.

FROM END OFCROSSWALK

SERVED

10.0m MAX.

ORIGINALLY DESIGNED LOCATIONOF POLE IS NOT SATISFACTORYFOR PED. HEAD. A PED. POLEIS ADDED AND PRIMARY POLELOCATION IS ADJUSTED.6.0mM

IN.

R.O.W.

1.5m MAX.

SW

SW

SW

CL



• if possible, poles with pushbuttons should bewithin the extended crosswalk lines or thepoles should be located within 1.5 m of theedge of the crosswalk being served;

• the poles should be located directly adjacentto, or within, sidewalks or other hard surfaceareas;

• the poles must be accessible and user friendly;not located beyond reach behind barriers or ingrass (mud) areas or areas where snowwindows will occur. Some additional sidewalkor paved shoulder may have to be coordinatedwith road designers;

• where possible, it is desirable that pedestrianpushbuttons be mounted on traffic signalpoles; where a separate pole is required, itshould be installed near the intersection ofthe centrelines of the crosswalks and shouldinclude the pedestrian heads to avoid visualclutter. In lieu of this treatment, a short polewith pushbuttons only may be used; and

• where a separate pole is required,consideration should be given to locating it atleast 6.0 m from other poles so as to allowroom for maintenance vehicles to operate andfor aesthetic reasons. This may require re-adjustment of previously designed locationsof primary and secondary poles. (Newconstruction only; not rehabilitation projects).Figure 40 illustrates these principles.

Poles With Pedestrian Heads

Poles carrying pedestrian heads should be located inaccordance with the following principles:

• pedestrian heads should ideally be locatedwithin the extension of the crosswalk lines orat a maximum of 4.5 m from these lines;

• the poles should be located so that standard38 mm dia. x 400 mm double arm bracketscan be used for pedestrian heads. The use ofmast arms longer than 600 mm with hangersis discouraged (unless unavoidable) due tointerference with maintenance vehicleoperations;

• pedestrian heads can be mounted on primary,secondary or auxiliary poles as long as theheads are not more than 10.0 m longitudinallyfrom the end of the crosswalk. (see Figure 40)

• ensure that the pedestrian heads will not bevisually blocked by vehicles at the stop line;

• pedestrian head locations should berestricted to the rear or sides of the poles.Mounting on the front (nearest the pavement)invites damage by errant large turningvehicles, snowplows, etc. The layoutdrawings should indicate the proper side ofthe pole for double arm bracket attachment;

• the addition of pedestrian heads to poles for otheruses may require re-adjustment of the previouslydesigned locations of these poles or even minoradjustments to sidewalk and crosswalk design(new construction only; not rehabilitationprojects).

5.13 Controller Locations

Coordination

The location of the traffic signal controllers may requiregrading, re-routing of ditches, etc. Co-ordination withthe road designer is required. For detailed informationon controller location design, refer to the Ministry’sElectrical Design Manual2.



Physical Requirements

Locations for controller cabinets must be designed withdue consideration given to safety, maintenance access,visibility of approaching traffic, service supply,grounding and electromagnetic interference. Thefollowing general guidelines apply:

• controller cabinets should be located on the“far right” corner of the Main Road at theintersection where possible. This givespersons, standing at the controller, the bestview of approaching traffic from both waysalong the Main Road;

• the head displays for 50% of the phasesshould ideally be visible while standing at thecontrollers;

• where barrier or guiderails are not present, itis desirable to locate the controllers at aclearance distance, equal to the clear zone inthe Ministry’s Roadside Safety Manual 22,from the edge, or projected edge, of throughlanes. Note that it is normally required , on roadconstruction or reconstruction projects, tomodify the grading and drainage design toaccommodate this requirement;

• controllers should not be mounted on slopessteeper than 6:1 nor at an elevationdifference of more than 1.0 m from thepavement;

• access to controllers should be directly off theshoulder or boulevard, without crossing ofditches, berms, walls, etc. if possible. Whereroad work is included in the contract,widening of the shoulder area with earth andgranular materials should be arranged with theroad designer;

• controllers should be located at a specificminimum distance from the groundelectrodes at the supply points. Refer to theMinistry’s Electrical Design Manual2 forgrounding details;

• controllers must be located at a specificminimum distance from overhead highvoltage wires to mitigate electromagnetic fieldinterference. Refer to the Ministry’s ElectricalDesign Manual2 for treatment;

• it is undesirable to have controllers, supplypoles, and primary poles in clusters whichcan be hit by an errant vehicle; wheresidewalks are present, and in suitablelocations, controllers may be sited at theproper offset distance from edge of pavementand immediately adjacent to the sidewalk;

• in congested urban areas (posted at 70 km/hor less) minimum clearances of 3.0 m fromedge of pavement are desirable. If this is notpractical, controllers should be located asclose to buildings as practical, leaving at leasta 1.5 m wide sidewalk area and keeping clearof doors and store-front windows;

• controllers to be installed on poles should beprovided with hard surfaces at grade so thatthey can easily be cleared of snow and avoidmuddy conditions for maintenance servicing;and

• controllers to be installed at ground levelshould be provided with concrete pads andconcrete or metallic pedestals in order toraise the bottoms of the cabinets aboveground and out of the snow (225 mmminimum suggested; more in snow belts).



5.14 Design Example

General

The design example in this section is presented indetailed format for a typical intersection. The exampleis intended to illustrate the principals of traffic controlsignal design and should not be applied to any specificintersection as each intersection has its ownidiosyncrasies.

The example shows an intersection which is to bereconstructed under a roadway contract but applicationsof the principles are equally valid for an existingintersection to be signalized.

Preparation Of Base Plan

This section emphasizes the importance of properpreparation of the base plan on which the signal designwill be carried out. The steps necessary to produce thebase plan are as follows:

• obtain the base plan mylar or CAD overlaysfrom the road designer. The plan should becomplete with existing and new edges ofpavement, islands, sidewalks, right-of-way, andlimits of paving (existing conditions preferablyscreened). It is not desirable to have other roaddesign notes such as “Limit of Construction”,nor items such as side slopes, drainage, orother roadway specific design features on thesignal design plan. It is however, convenient tohave limiting factors such as ditches on theplan. A print of the design plan should beobtained showing other road informationshould be obtained for coordination ofphysical features;

• obtain the locations of all existing utilities fromthe road designer or from the utilitiescoordinator. Obtain any known utilityrelocation proposals or obvious relocationsrequired at this time (utility locations must bestaked and verified during construction);

• obtain the details of the existing signal system(where applicable) from previous contractdrawings, signal drawings or legal approvaldrawings;

• carry out a site inspection with appropriatestakeholders including the local SupplyAuthority representative and the utilitiescoordinator. At this meeting, attempt toestablish the basic routing of the finaloverhead electrical lines, the possiblelocations of power supply points, if metering isrequired, if utility pole mounting of the powersupply cabinet is allowed and any specialdetails required by the local Supply Authority.Try to determine the location of future utilitypoles which could be used for signal armmounting. Note that final decisions are notusually possible at this time, but a good basisfor the preliminary layout can normally beobtained for further coordination;

• note that if the project is for the installation ofthe traffic control signals only, the depths ofthe utilities may also be indicated on the plan;

• plot all information accurately (to scale) onthe base plan;

• the base plan, showing existing features,utilities and relocations of the example will besimilar to the plan shown in Figure 41 (page118) at this point.

Note that it is the policy of some road authorities tohave utilities relocated prior to construction. This mayrequire prior relocation of the power supply cabinetand even minor pole or mast arm relocations by theelectrical maintenance staff or by pre-constructioncontract since the road/signal contractor is not onsite when the utilities are being relocated. It is thedesigner’s responsibility to prepare a sketch andoutline of the work required and to bring these itemsto the attention of the roadway project manager andthe person in charge of electrical maintenance so thatappropriate arrangements for the work can be made.



Pole Locations

This section deals with the fact that there are manylocations at an intersection where it is impossible orimpractical to install traffic signal facilities. Poles aremost prone to these restrictions due to the depth ofthe footings (possible interference with undergroundutilities) and the height of the poles (possibleinterference with overhead utilities).

It is important that the designer recognize therestricted areas from the beginning to the end of thedesign. To assist in the design, it is suggested thatthe restricted pole locations be plotted directly on theworking plan prior to beginning the layout. Note thefollowing:

• utility clearance rules should follow thosegiven in Subsection 5.11;

• the range of restricted pole areas, whichshould not be exceeded, should be plottedfrom the information given in Section 5.6;

In some cases, actual relocations are not required asthe old utility pole is purchased and cut off, with newaerial cable feeds installed and old pole mountedequipment left in place as an interim measure.

Layout Of Crosswalks And Sidewalks

This section uses the principles of Subsection 5.10 tolayout or confirm the locations of crosswalks andconfirm or suggest the location of sidewalks as a firststep in the actual signal layout design.

Figure 42 shows the layouts required with somesuggested modifications to the sidewalk design. Notethat the locations of the crosswalks and sidewalks atthis time are preliminary and remain to be coordinatedwith road designers. The signal layout must first becarried out to confirm the most desirable sidewalk layoutand those features which may be changed or improvedtowards an integrated design. This should also becarried out in the case where only signal provisions areto be installed.

Figure 41 - Base Plan Features

NOTE: District to relocate existing service during hydro relocation

PCA

PCA

G

H

PCU

PCU

H

CCA

TO BE RELOCATED

FINAL LOCATIONG G

CCAB CCA

TS

TS

TS& L

TS & L

TS & L

TS

H&BP

CA

CC

AW

CCA

CCA

B

G

TS

& L

EXISTING PAVEMENT

PCA

CC

A

FINAL LOCATION

TO BE RELOCATED

H&BPCA

PC

AC

CA

W



Figure 43 (page 120) shows the working plan of theexample with utility restrictions marked.

Pre-set Head and Pole Locations

This section deals with signal head and pole locationswhich are normally set in a standard or mandatorylocation by rules as outlined in Subsection 5.3. Thesepoles are the first to be pre-set in any design. In theexample, the median island poles on the main roadshould obviously be set in standard locations as theareas are normally free of interference from utilities(to be checked). Figure 44 (page 121) shows thestandard signal head and median poles locations setin the example.

Layout Of Primary And Secondary Heads

Using the principles of Subsections 5.6 and 5.12, theprimary and secondary heads and poles are laid out asshown in Figures 45 (page 122) and 46 (page 123).

Layout Of Pedestrian Facilities

Using the principles of Subsection 5.12, the pedestrianfacilities are laid out as shown in Figure 47 (page 124).

Checking Layout

This section deals with the checking of the layout designusing the principles of Subsections 5.5 and 5.12.Figure 48 (page 124) shows manual checking of thecones of vision and checking for blocked signal heads.The distances between heads and the pedestrianfacilities should also be checked for conformance withthe principles of Subsection 5.12.

Figure 42 - Crosswalk and Sidewalk Modifications

PCAH

SUGGESTEDS.W. MOD.

SUGGESTED S.W. MOD.G G

CCACCA

PROPOSED CROSSWALK

SUGGESTEDCROSSWALKMODIFICATION

H&B

PC

AC

CA

WCCA PROPOSED SIDEWALK

SUGGESTEDS.W. MOD.

B

G

SUGGESTEDS.W. MOD.

CC

A

H&BPCA

H

PC

AC

CA

W



A checklist is provided in Appendix C.

Controller And Power Supply Locations

The controller should be located in accordance withthe following principles:

• strict attention should be paid to the principlesof good grounding and relative freedom frominterference from overhead hydro lines as givenin Subsection 5.11 and as elaborated on in theMinistry’s Electrical Design Manual2;

• in areas of 80 km/h posted speed or greater, acontroller offset of 10 m from the throughedge of pavement is desirable; an offset of6 m is acceptable. This location ofteninterferes with ditches (the roadway shouldbe visible from the controller site) andcoordination with the road designer isrequired as outlined in Subsection 5.13;

• electrical maintenance and traffic staff shouldbe consulted as to their preference of cabinetorientation. Some prefer the front door to befacing oncoming traffic, and some prefer tostand at the front door and face theintersection. Unless otherwise known, therecommended location is at a 45o angle tothe intersection as shown in Figure 49 (page125);

• the location of the power supply pole hassome bearing on controller location; it isdesirable to have the power supply less than75 m from the controller and it is desirable tohave the controller more than 11 m from thepower supply pole due to the possibility of adouble pole knock-down upon vehiclecollision; and

• for system use, the location of thecommunications connection has a bearing;separate ducts are required between theconnection point and the controller.

Figure 43 - Pole Areas Restricted by Utilities

MIN. 3.0m CLEAR FROMTHROUGH EDGE OF PAVEMENT

PCA H

DESIRABLE TOKEEP 5.0m AWAYFROM HYDRO LINE(HORIZ.) OR 3.0mAWAY VERTICALLY(VARIES WITHVOLTAGE)

C

B

B

C

CCA

MIN. 1.5m CLEAR OFEDGE OF PAVEMENT

150mm CLEAR TOCOMM. LINES

CCAH&B

CCAP

CA

CC

AW

G

B

ALLOW AT LEAST 1.0m CLEARANCETO UNDERGROUND UTILITIES (0.5mIF LOCATION IS ACCURATELY KNOWN)

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W



The power supply cabinet should be located inaccordance with the following principles:

• the cabinet may be mounted within a groundmounted pedestal designed for the purpose.Common communications pedestals are notstrong enough for this application;

• the cabinet may be mounted on a utility pole ifthe local Supply Authority permits this. It ispreferred that the utility pole not have atransformer as the transformer ground cancause interference with the power supplyground. The local Supply Authority should beapproached to install their grounds at leastone pole span away (see the Ministry’sElectrical Design Manual, Part 2, Chapter 9,”Grounding”) 2;

• the power supply cabinet may be mounted ona separate pole suiting the purpose, may be fedaerially or underground and may have anelectrical energy meter;

• the power supply cabinet should be within 75m of the controller and should be visible fromboth the controller and the roadway. It shouldalso be located at least 10 m from the edge ofpavement if possible.

Detector Layout

Detector loops are laid out with consideration of thearea of dilemma zone detection as per Table 27 forextension loops on roadways posted at 80 km/h andover and as shown in Figure 25 for presence loops.The loops are designed using the principles of theMinistry’s Electrical Design Manual, Part 2, Chapter 2,“Vehicle Detection” 2.

Figure 50 (page 125) shows the detector loops laidout for the example. Note that there are two ways tonumber the loops; beginning at the controller, the loopsare numbered clockwise (as shown). This methodcorresponds with that used in some asset management

Figure 44 - Pre-set Signal Locations

PCA H

C

B

B

C

CCACCA

H&B

CCAP

CA

CC

AW

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W9

3.0

SECONDARY HEADSWITH 600mmMAST ARMS

P2

9P1

3.0



system software. An alternative method uses thenumbers of the phase movements served and A, B,C.... for multiple loops serving a movement commonto the lanes involved.

Duct And Wiring Systems

Careful consideration must be given to the design ofthe underground ducts and electrical chambers due totheir large cost, the possibility of prolonged trafficinterference, the possibility of utility interference andpossible damage to roadbed structure caused by theirinstallation or failure.

Underground ducts and wiring are not prone to damagefrom over-height vehicles and are aesthetically desirableto overhead wiring. The recommended practice for thedesign of duct systems is given in the Ministry’sElectrical Design Manual, Part 2, Chapter 5, “DuctSystems” 2.

Figure 51 (page 126) shows the underground systemdesigned for the example intersection.

Coordination Of Lighting Design

Roadway lighting shall be required at all signalizedintersections. The illumination warrant may be partialor full depending on roadway and traffic conditions.While in many municipalities, most roadways alreadyhave full illumination, roadways without illumination,such as at isolated rural intersections, shall be providedwith at least two lighting luminaires to provide partialillumination. The lighting system should be integratedwith the signals according to the following principles:

• the lighting should be installed oncombination signal and lighting poles wherepossible. Utility poles may also be used if theSupply Authority allows this;

• all lighting on combination poles should becontrolled from a combination power supplycabinet;

Figure 45 - Primary Head and Pole Layout

PCA H

C

B

B

C

CCACCA

H&B

CCAP

CA

CC

AW

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W

2.0

7.5

P2

9P3

7.4

0.5

8.0

EP1

2.0

7.4

0.5

7.5

P5

1.650.5

P4

P1

9



Figure 52 (page 126) shows a typical partial lightinglayout combined with the signals for the example.Partial lighting should be installed on the “far right”side of each approach of the main road. The lightingis typically integrated on a combination or joint-usepole with the signals as indicated in Figure 52. Notethat a small adjustment in the pole locations may berequired to obtain the proper lighting and clearances,otherwise separate poles may be installed as long asthey are a minimum of 6 m from the signal poles andclear of utilities.

• Different voltages and different sources ofsupply are not allowed by the Ontario ElectricalCode unless multiple provisions are carried out;

• a # 6 system ground for the signal poleinterconnection is recommended to serve asthe lighting system ground. The ground cablemust be insulated to conform to the CanadianElectrical Code. Refer to the Ministry’sElectrical Design Manual, Part 2, Chapter 9,“Grounding” 2.

Figure 46 - Secondary Pole and Head Layout

PCA H

C

B

B

C

CCACCA

H&B

CCAP

CA

CC

AW

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

WP5 EP2

1.0mMIN.

P4

P1

9

P2

9

P3

>10m

P6

0.8

1.0mMIN.

7.5

EP1



Figure 47 - Layout of Pedestrian Facilities

Figure 48 - Checking Signal Head Visibility and Layout

PCA H

C

B

B

C

CCACCA

H&B

CCAP

CA

CC

AW

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W9

P2

P3

P6

EP1

P7

6m M

IN.

9

P1

P4

P5

6mMIN.

EP2

PCA H

C

B

B

C

CCA H&B

CCA

PC

AC

CA

W

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W

P5 EP2

P4

P1

9

P2

9

P3

P6

EP1

1.0m

1.0m15

SIGNAL VISIBILITY DISTANCE

1.0m

P7



Figure 49 - Controller and Power Location

Figure 50 - Detector Loop Layout

P3

SUPPLY LOCATION 'A'1 ¯, 3 WIRE,120 / 240 V

P2

TC1

LD3 MH3

P19

9

P7

P6MH1EP1

G

HPCA

C

MH2

PCA

PC

AC

CA

WP

CA

CC

A

G

P4

GCCA

EP2

PC

AC

CA

WH&B

B P5CCA

CG

G

B

LD10

LD2LD1

LD5

LD7 LD6

PCA H

C

B

B

C

CCA H&B

CCA

PC

AC

CA

W

G

B

CC

A

PCAHH&B

PC

AC

CA

W

PC

AC

CA

W

P5 EP2

P4

P19

P2 9

P3

P6

EP1

P7

SUPPLY LOCATION 'A'1¯, 3 WIRE,120 / 240V

G

TC1

DISTANCE AS PER TABLE A 1.4LD3

LD4

DISTANCE AS PER TABLE A 1.4

LD9

LD8



Figure 52 - Partial Lighting

Figure 51 - Underground Duct System Layout

P3


P2

LD1 LD2

TC1

LD5

MH6

LD6

LD4

LD3 MH3

P19

9

P7

P6MH1EP1

G

HPCA

C

MH2

PCA

PC

AC

CA

WP

CA

CC

A

G

P4

GCCA

MH4EP2

PC

AC

CA

W

H&BB

MH5

P5CCA

CG

G

B

P3


P2

LD1 LD2

TC1

LD5

MH6

LD6

LD4

LD3 MH3

P19

9

P7

P6MH1EP1

G

HPCA

C

MH2

PCA

PC

AC

CA

WP

CA

CC

A

G

P4

GCCA

MH4EP2

PC

AC

CA

W

H&BB

MH5

P5CCA

CG

G

B



6. MISCELLANEOUS

6.1 General

This part of the manual contains information on variousmiscellaneous aspects of traffic signal design andoperation as well as some hardware information.

6.2 Standard Equipment

Maintenance staff stock standard equipment used forreplacement purposes. No variation in the use ofstandard equipment should be considered withoutreviewing the need for such variation with the personin charge.

The design of signals is not an architecturalcompetition although some municipalities makeallowances for special equipment for downtownbeautification schemes, prestige routes, etc. The bestpractice is to make each set of signals as close tostandard as is practical since anything out of theordinary may cause motorist hesitation and thereforemay affect safety. The Ministry uses Ontario ProvincialStandards Drawings (OPSD) for traffic signal purposes.

6.3 Other Considerations

Structural Considerations

Many components of traffic control signal hardwaremust have structural integrity. In many cases,manufacturers of items, such as poles and mast arms,design to an AASHTO code and the resultant designsare then checked to the requirements of the OntarioHighway Bridge Design Code (OHBDC) before beingincluded in the Ministry’s List of Designated Sources.

Other items requiring structural checking or approvalare pole footings and electrical chambers. In the caseof pole footings, the design should meet therequirements of the OHBDC for proper protectionagainst legal liability in the event of a mishap or in theevent of windy weather conditions causing failure. Inthe case of electrical chambers, the loading by vehiclesshould also meet the OHBDC for liability and cost ofreplacement reasons.

Electrical Considerations

Traffic control signal design has traditionally beenmanaged or approved by traffic engineers since thesignals are a tool of traffic management and regulation.A large portion of the hardware and, of course, thewiring are electrical devices. The recommendedpractice with regard to electrical design of trafficcontrol signals is:

• where in-house design capability does notexist, a consulting engineering firm withelectrical design expertise in traffic signalsmay be selected;

• for each area or municipality, a range ofequipment options and methods of wiring isavailable for use by the designer with the areaor municipality preferences being usedconsistently;

• all electrical equipment items should be CSAapproved, UL approved or have Ontario HydroSpecial Inspection approval as a safetymeasure and as part of a pro-active riskmanagement process. A traditional exceptionto this is controllers which are specificallymanufactured to set standards (such as NEMAstandards) for the traffic signal industry;

• where contracts for the traffic signalinstallation work are let, the contractors shoulduse qualified licenced electricians for the wiringand qualified IMSA Technicians for the



• locations of corner poles with pushbuttons arethe source of local complaints if the poles arenot installed to be compatible with sidewalks,are behind barriers, have the pushbuttons onthe wrong side or are sited to leave a few stepsin the mud in order to reach the pushbutton;

• where buildings are adjacent to the sidewalk,the poles should be sited such that nointerference occurs with doors, windows andcommercial signs. Spaces between poles andbuildings should be a minimum of 1.5 m toallow for the sidewalk snowplow or should beclosed to allow no more than a 450 mm space.(This may lessen the sidewalk width in tightspaces and will require agreement by theowners of the buildings.);

• signal arms should project about 1.5 m beyondoverhanging tree branches so that future treetrimming can be controlled without excessivetrimming of large branches;

• controller pads should be kept parallel to theroadway, particularly in urban areas. Wherepractical, the controller pad can be directlyadjacent to and flush with the sidewalkprovided that offset rules are observed. Incongested urban areas, care should be taken toplace the controller free of store doors,windows, etc. and as clear of sidewalks aspractical so as to provide a minimum 1.5 msidewalk space;

• excessive equipment on poles, particularlyutility poles with external conduits, straps, etc.can be unsightly;

• long signal arms on utility poles tend to tiltthese poles towards the roadway. Guy anchorswith sidewalk struts behind the mast armattachment brackets keeps these installationsneater. This should be discussed with thepower Supply Authority as to need and as towho should do the work.

controller setup. The contractor should obtaininspection and certification of a qualified staffelectrical technician, qualified electrician orqualified electrical engineer;

• the power supply cabinet and the groundingare subject to inspection by Ontario Hydro andthe power is not connected by the localelectrical Supply Authority until this approvalhas been obtained.

Aesthetic Considerations

Although aesthetics play a minor part in the functionalityof a traffic signal system, it should be kept in mind thatlocal citizens see the equipment on an everyday basisand a cer tain amount of local pride in theirneighbourhood is natural. Since standard equipmentis used in most installations, the treatment of aestheticvalues consists mainly in avoidance of treatments whichare not considered to be very pleasing. Some examplesare:

• the number of poles should be kept to aminimum;

• the signal head displays and traffic signals arethe only items which we really want toconsciously “see”. Poles and all otherequipment should be as inconspicuous aspractical;

• the length of single member arms should bekept to the minimums required to satisfy thecriteria;



6.4 Lamps, Lenses & Visors

Lamps

Lamp data is given in Table 27. The lamps are chosenfor compliance with ITE specifications for luminousoutput and for ruggedness and relative longevity.Incandescent lamps shall meet the generalrequirements of CSA C22.2, No. 84, and ITE ST-017.

Many municipalities use equivalent 69 Watt lampswith a minimum of 595 rated initial lumens for amberand green displays where the traffic signals are closetogether, such as in a downtown area, and where theposted speed is 60 km/h or less.

Lenses

Predominantly, lenses should be of the standardprismatic plastic refractors meeting the chromaticityrequirements of ITE Specification Vehicle TrafficControl Signal Heads contained in ITE Publication No.ST-017.

Exceptions to the standard lenses include opticallyprogrammable lenses, fibre optic lenses and lightemitting diode lenses. Optically programmable lensesinclude a lens assemblies which can be set to producea narrow cone of light such that the lenses do notappear to be illuminated from other than the traffic

lanes which they serve. These lenses are used wheremultiple approaches may cause motorist confusionsuch as at the second intersection of a very close setof intersections, on signalized service roads close toa freeway and for left turns in a wide median wherethe through traffic is not signalized.

Signal indications using Light Emitting Diodes arebeing used in some jurisdictions in order to saveenergy and energy costs. Caution should be exerciseduntil these types of signal heads standardize.Performance requirements are given in ITE PublicationST-021, Proposed Interim Purchase Specification: LightEmitting Diode (LED) Vehicle Traf fic SignalsAssemblies.19

Visors

Visors must be used on all signal display assembliesto minimize the return of outside light through thelenses which can cause the optical assemblies to appearilluminated. Normally, standard cowl visors with ashaped top and open bottom will suffice but wherethe sun strikes the lenses, particularly at low glancingangles, the phenomenon known as sun phantom maycause the optical assemblies to appear illuminated. Insuch cases, long cowl visors or tunnel visors shouldbe employed.

Table 27 - Communly Used Lamps for Traffic Signals

Lens TypeLens Size(cm)

LampCentreLength(mm) Argon Krypton Argon Krypton

Lamp Wattage Lamp Life (h)Lamp Voltage

Lamp Type

30

20

30

30

75

63

75

75

150

100

100

100

135

90

90

90

125 Clear, traffic

Clear, traffic

Clear, traffic

Clear, traffic

125

125

125

6000

8000

8000

6000

8000

8000

8000

8000

All (round)

All (round)

Pedestrian(square)

Arrow



APPENDIX AGLOSSARY



ACRONYMS

AASHTO: American Association of StateHighway and TransportationOfficials;

AC: Alternating Current;

AC+: 120 V a.c., 60 Hz power bus;

AC-: The 120 V a.c., 60 Hz neutral busgrounded at the power source;

ASTM: American Society for Testing andMaterials;

AWG: American Wire Gauge;

CCG: Canadian Capacity Guide forSignalized (Urban) Intersections;

CMOS: Complimentary Metal OxideSemiconductor;

CPU: Central Processing Unit;

CTS: Clear to send;

DCE: Data communications equipment;

DCP: Data channel port;

DDE: Data distribution equipment;

DHV: Design Hourly Volume;

DTE: Data terminal equipment;

EEPROM: Electrically Erasable ProgrammableRead Only Memory;

EPROM: Erasable Programmable Read-OnlyMemory;

FHWA: Federal Highway Administration (U.S.A.);

HCM: Highway Capacity Manual;

HOV: High Occupancy Vehicle;

IPS: Intersection Pedestrian Signals;

ITE: Institute of Transportation Engineers;

LED: Light emitting diode;

LOS: Level of Service;

LTL: Left Turn Lane;

MIST: Management Information System forTraffic;

MODEM: Modulate/Demodulatecommunications interface Unit;

MOS: Metal Oxide Semiconductor;

MOV: Metal Oxide Varistor;

MPU: Microprocessor Unit;

MTO: Ministry of Transportation, Ontario;

MTTR: Mean time to repair;

MUTCD: Manual of Uniform Traffic ControlDevices;

NEMA: National Electrical ManufacturersAssociation;

OTM Ontario Traffic Manual

PCB: Printed Circuit Board;



PHF: Peak Hour Factor;

PHV: Peak Hourly Volume;

PIT: Pre-Installation Testing;

POP: Proof of Performance Testing;

PROM: Programmable Read-Only Memory;

PXO: Pedestrian Crossover;.

RAM: Random Access Memory;

RF: Radio Frequency;

RTS: Request to send;

RXD: Receive data;

SCOOT: Split Cycle Offset OptimizationTechnique;

TAC: Transportation Association of Canada;

TOC: Traffic Operations Centre (general);

TOD: Time of Day;

TTL: Transistor-Transistor Logic;

TXD: Transmit data;

UART: Universal Asynchronous Receiver/Transmitter;

VDS: Vehicle Detection Station.

DEFINITIONS

Actuation:The operation of a detector in registeringthe presence or passage of a vehicle orpedestrian.

All Red Interval:The time in seconds of a red indication forall intersection traffic. It is used followingan amber clearance interval to permitvehicles or pedestrians to clear theintersection before conflicting trafficreceives a green indication.

Amber Clearance Interval:The first interval following the green right-of-way interval in which the signalindication for that phase is amber. Aclearance interval to warn approachingtraffic to clear the intersection beforeconflicting traffic receives a greenindication.

Cabinet:An outdoor enclosure for housing aController Unit and associated equipment.

Call:A registration of a demand for right-of-wayby traffic (vehicular or pedestrian) at acontroller.

Central Computer:The combination of the applicationsoftware, operating system, and computerhardware operating a traffic signal systemfrom a single location.

Colour Sequence:A predetermined order of signal indicationswithin a cycle.



Concurrent Timing:A mode of controller operation whereby atraffic phase can be selected and timedindependently and simultaneously with another traffic phase.

Conflicting Phases:Two or more phases which will causeinterfering traffic movements if operatedconcurrently.

Conflict Monitor:A device used to continually check for thepresence of conflicting signal indications andto provide an output in response to conflict.

Controller:The general usage term for the controller unit,cabinet and associated appurtenances.

Controller Cabinet:An outdoor enclosure used for the housingof a controller unit and all associated power,control, protection, activation orinterconnection devices.

Controller Unit:That part of the controller which performsthe basic timing and logic functions. Amicroprocessor based or electro-mechanicaltiming unit.

Coordination:The control of controller units in a manner toprovide a relationship between specific greenindications at adjacent intersections inaccordance with a time schedule to permitcontinuous operation of groups (platoons) ofvehicles along the street at a planned speed.

Cycle:Any complete sequence of traffic controlsignal indications. In an actuated controllerunit, a complete cycle is dependent on thepresence of calls on all phases. In a pretimed

controller unit, it is a complete sequence ofsignal indications.

Cycle Length:The time (in seconds) required for onecomplete sequence of signal indications.

Cycle Splits:The times in percent of the cycle for thephases making up the cycle.

Density:A measure of the concentration of vehiclesusually stated as the number of vehicles perkm per lane.

Detection Zone:That area of the roadway within which avehicle will be detected by a vehicle detector.

Detector:A device for indicating the presenceor passage of vehicles including sensordevice, lead-in cable and detector sensor(amplifier) unit.

Detector Loop:A detector that senses a change ininductance of its inductive sensor loopcaused by the passage or presence of avehicle in the detection zone of the loop.

Detector Memory:The retention of an actuation for futureutilization by the controller unit.

Detector Mode:A term used to describe the operation of adetector channel output when a presencedetection occurs: (1) Pulse Mode: Detectorproduces a short output pulse whendetection occurs. (2) Controlled Output: Theability of a detector to produce a pulse thathas a predetermined duration regardless ofthe length of time a vehicle is in the detection



zone. (3) Continuous-Presence Mode:Detector output continues if any vehicle (firstor last remaining) remains in the detectionzone. (4) Limit-Presence Mode: Detectoroutput continues for a limited period of timeif vehicles remain in the detection zone.

Display:A display consists of the total illuminatedand non-illuminated signals facing themotorist. “Display” is interchangeable with“Indication”.

Downloading:The transmission of data from a master orcentral computer system to a slave or aremote Controller Unit.

Dwell:The interval portion of a phase when presenttiming requirements have been completed.“Rest” as in “rest in green”.

Extendible Portion:That part of the green interval in an actuatedphase following the initial portion which maybe exceeded by traffic actuations to theMaximum Green.

Flasher:A device used to open and close signalcircuits at a repetitive rate.

Force Off:A command to the controller unit that willforce the termination of the current right-of-way (green) interval during the extendibleportion.

Fully Actuated:(1) A fully actuated mode of operation isone in which both the side (minor) road andthe main (major) road utilize detectiondevices. During operation, if no actuationoccurs at the intersection, the controller will

either rest in the last phase actuated or returnto main road green to rest (recalled to mainroad green). (2) A fully actuated mode ofoperation can be one in which passage loopsare used on all approaches, or on one of theroads if the other has detection at theintersection.

Gap Reduction:A controller feature whereby the unitextension or allowed time spacing betweensuccessive vehicle actuations on the phasedisplaying the green in the extendible portionof the intervals is reduced after eachextension, usually in proportion to anotherparameter. Time Waiting Gap Reduction is afeature whereby the unit extension in thephase having the green is reduced inproportion to the time vehicles have waitedon the phases having the red.

Hold:A command to the controller unit whichcauses it to retain the existing right-of-way(green) interval.

Indication:The illumination of a traffic signal lens orcombination of signal lenses at the sametime. The “Display”.

Initial Portion:The first timed part of the green interval ofan actuated phase.

Interconnected Controller:A controller which operates traffic controlsignals under the supervision of a mastercontroller.



Interconnection:(1) A means of remotely controlling some orall of the functions of a traffic control signal.(2) An electronic, fibre optic, timesynchronization, radio, telephone or electricalconnection with coordination units ormodems in the controller cabinets; thephysical interconnection.

Interval:A part of a phase that is individually timedby the controller unit.

Interval Sequence:The order of appearance of signal indicationsduring successive intervals of a cycle.

Loadswitch:A device used to switch 120 Volt power tothe traffic control signal heads. Loadswitchesare normally semi-conductor devices whichare switched by a low voltage signal fromthe controller unit.

Main Road:The roadway approach or approaches at anintersection normally carrying the highestvolume of vehicular traffic (also called “MajorRoad”).

Master Controller:An automatic device for supervising a systemof controllers, maintaining definite timeinterrelationships, selecting among alternateavailable modes of operation oraccomplishing other supervisory functions.A Master Controller which controls one ormore slave controllers.

Maximum Green:The maximum time the right-of-way can beextended by actuations on a phase providedan actuation has been registered on aconflicting phase.

Military Specification:Current issues and/or revisions of standardsor specifications issued by the U.S.Department of Defence.

Minimum Green:The shortest time for which the right-of-wayshall be given to a non-actuated phase; or toan actuated phase provided that an actuationhas been registered for that phase.

Module:A removable assembly with a fixed patternof pixels and identical to all other modules.

Motherboard:A Printed Circuit Connector Interface Boardwith no active or passive components.

Movement:A movement is the direction of traffic flowand may be straight ahead (a “throughmovement”), a green left arrow (a “left turnmovement”), etc. Several movements maybe allowed within a phase (such as with anadvanced green arrow and a circular greendisplay). In some cases, a movement is calleda faze since it is normally part of a phase.

Non-conflicting Phases:Two or more traffic phases which will not bein conflict with each other if operatedconcurrently.

Offset:The number of seconds or percent of cyclelength that a defined time-reference point (the“yield point”, normally the start of main streetgreen) at the traffic control signal occurs afterthe time-reference point of a master controlleror of an adjacent traffic control signal.



Opposing Traffic:Traffic progressing in the upstream oropposite direction to the traffic beingconsidered on a roadway.

Overlap:A right-of-way indication that is derived fromthe service of two or more traffic phases.

Passage Detection:The ability of a vehicle detector to detect thepassage of a vehicle moving through thedetection zone and to ignore the presenceof a vehicle stopped within the detectionzone.

Passage Time:(1) see Unit Extension Time. (2) The timeallowed for a vehicle to travel at a selectedspeed from the detector to the stop line.

Pattern:A unique set of coordinationparameters including cycle length, splitvalues, offsets and sequence of intervals.

Pedestal:Ground mounted enclosure forcommunications or a support for a controllercabinet.

Pedestrian Clearance Interval:The time in seconds during which the orangehand is flashed, starting after a walkingpedestrian indication and ending beforeconflicting vehicles receive a green indication(may include the vehicle amber time).

Phase:A part of a cycle where one or more trafficmovements receive a green indication at thesame time. Phase time is the time requiredfrom the start to the finish of the phaseincluding amber and all-red interval times.

Phase Sequence:A predetermined order in which the phasesof a cycle occur.

Phase Skip:A function used to provide omission of aphase in the absence of actuations on thatphase.

Plan:A unique set of timing values, intervals usedand sequence of intervals that is stored in orsent to a controller unit. Different plansmay be used for time of day, time of week,special events and so on or may be trafficresponsive as determined by detectoractuation.

Poll:An enquiry message sent from a master to aslave on a regularly timed basis to solicit thestatus of the slave.

Power Failure:A power failure is said to have occurred whenthe incoming line voltage falls below 93 (+2)VAC for 50 milliseconds or longer. Thedetermination of the 50 milliseconds intervalshall be completed within 67 milliseconds ofthe time the voltage falls below 93 (+2) VAC.

Power Restoration:Power is said to be restored when theincoming line voltage equals or exceeds 95VAC for 50 milliseconds or longer. Thedetermination of the 50 millisecond intervalshall be completed within 67 milliseconds ofthe time the voltage first reaches 98(+2 )VAC.



Pre-emption:The transfer of the normal control of signalsto a special signal control mode for thepurpose of servicing railway crossings,emergency vehicle passage, transit vehiclepassage and other special tasks, the controlof which require terminating normal trafficcontrol to provide priority needs of the specialtask

Pre-emptor:A device or program/routine which providespre-emption.

Presence Detection:The ability of a vehicle detector to sense thata vehicle, whether moving or stopped, hasappeared in its field.

Pretimed:A controller unit mode of operation of trafficcontrol signals with predetermined fixed cyclelengths, fixed interval durations and fixedinterval sequences.

Progression:1) The time relationship between adjacentsignals on a roadway which permits a platoonof vehicles to proceed through the signals ata planned rate of speed. 2) The act of variouscontroller units providing specific greenindications in accordance with a timeschedule to permit continuous operation ofgroups (platoons) of vehicles along the roadat a planned speed.

Red Clearance Interval:A clearance interval which may follow anamber clearance interval that in theory allowstime at the end of a phase for vehicles in theintersection to clear prior to release of aconflicting phase.

Right-of-way:The operation of a controller in causing trafficcontrol signals to display indicationspermitting vehicles or pedestrians to proceedin a lawful manner in preference to othervehicles or pedestrians.

Semi-actuated:Operation by a type of traffic-actuatedcontroller in which means are provided fortraffic actuation on one or more but not allapproaches to the intersection.

Side Road:The roadway approach or approaches at anintersection normally carrying the leastvolume of vehicular traffic (also called “MinorRoad”).

Signal Indication:The illumination of one or more lenses in asignal head which conveys a message totraffic approaching the signal from onedirection.

Slave Controller:A slave controller is an intersection trafficsignal controller which is locally programmedto suit the interval times required at theintersection but which is set on the phasingand timing of the system as determined bythe master controller or central computer.

Split:For an actuated controller unit, a division ofthe cycle length allocated to each of thevarious phases (normally expressed inpercent). For a pretimed controller unit, splitis the time allocated to an interval.



System:A traffic signal system is composed of anumber of traffic signal controllers operatingfrom electronic instructions given by a mastercontroller at one of the intersections or givenby a central computer at a traffic control/operations centre. A system may be installedon a single roadway with one mastercontroller and one or more slave controllersor on a grid of roadways using either a mastercontroller or a central computer. A systemmay use interconnection methods ortelephone or able television networks or anycombination thereof for communicationstransmission of data commands to the localslave controllers

Through Band:The time period between the passing of thefirst and last possible vehicle in a group ofvehicles moving in accordance with thedesigned speed of a signal progression.

Time Base Control:A means for automatic selection of modesof operation of traffic control signals in amanner prescribed by a predetermined timeschedule.

Traffic Control Signal:Any power operated traffic control device,

whether manually, electrically ormechanically operated, by which traffic isalternately directed to stop and permitted toproceed. Traffic Signal: 1) When used ingeneral discussion, a traffic signal is acomplete installation including signal heads,wiring, controller, poles and otherappurtenances.(2) When used specifically,the term refers to the signal head whichconveys a message to the observer.

Unit Extension:The timing period during the extendibleportion of a right-of-way interval which isresettable by each detector actuation withinthe limits of the maximum period (extensionlimit).

User-definable Parameters:Parameters which can be modified on-line

by the user via some interactive dialoguewith the system.

Watchdog:A circuit or timer that is used to watch thatan appropriate action is taken on a regularbasis.

Yield:A command which permits a controller unitto transfer right-of-way.



APPENDIX BREFERENCES



REFERENCES

1. Canadian Capacity Guide for SignalizedIntersections, Institute of TransportationEngineers, District 7 -Canada, 1995.

2. Electrical Design Manual, Ministry ofTransportation, Ontario, 1989.

3. Electrical Maintenance Manual, Ministry ofTransportation, Ontario, 1989.

4. Equipment and Material Standards of theInstitute of Transportation Engineers;Institute of Transportation Engineers,Publication No. ST-017, 1995.

5. Geometric Design Manual, AmericanAssociation of State Highway Officials, 1996.

6. Guide to Traffic Engineering Practice -Traffic Signals, Austroads, 1993.

7. Highway Traffic Act (HTA), OfficeConsolidation, Revised Statutes of Ontario,1990, Chapter H.8 and the Regulationsthereunder (as amended); Queen’s Printer forOntario, March, 1996.

8. Highway Capacity Manual, TransportationResearch Board, 1994.

9. Left Turn Phase Criteria, MetroTransportation Report, 1995.

10. Manual of Uniform Traffic ControlDevices, Ministry of Transportation, Ontario,1985.

11. Manual of Uniform Traffic ControlDevices, U.S. Department of Transportation,1997.

12. Manual of Uniform Traffic ControlDevices, Transportation Association ofCanada, 1997.

13. Occupational Health and Safety Act(OHSA) - Revised Statutes of Ontario,Queen’s Printer for Ontario, 1978.

14. Ontario Highway Bridge Design Code -Ministry of Transportation, 1994.

15. Ontario Provincial Standard Drawings,Volume 3, Electrical Drawings, Division 1000.Ministry of Transportation, Ontario andMunicipal Engineering Association.

16. Ontario Traffic Signal Control EquipmentSpecifications, Ministry of Transportation,Ontario, 1994.

17. Pedestrian Crossing Time at SignalizedIntersections, Metro Transportation, TrafficBranch Operating Practice, 1995.

18. Preemption of Traffic Signals At or NearRailroad Grade Crossings with ActiveWarning Devices, Recommended PracticeFor, ITE, 1997

19. Proposed Interim Purchase Specification:Light Emitting Diode (LED) Vehicle TrafficSignals Assemblies. ITE Publication ST-021,Institute of Transportation Engineers.

20. Standard Specifications for StructuralSupports for Highway Signs, Luminairesand Traffic Signals, American Associationof State Highway and Transportation Officials,1992.

21. Regulations for Railway and RoadwayLevel Crossings; Queen’s Printer for Canada,April, 1984.

22. Roadside Safety Manual, Ministry ofTransportation, Ontario, 1995.

23. Traffic Signal Control at OffsetIntersections, Report to TransportationCommittee, Metro Transportation, 1991.

24. Traffic Control Systems, NEMA StandardsPublication No. TS 1, National ElectricalManufacturers Association, 1989.



25. Traffic Control Signal Timing and CapacityAnalysis at Signalized Intersections,Ministry of Transportation, Ontario, 1989.

26. Traffic Controller Assemblies, NEMAStandards Publication No. TS 2, NationalElectrical Manufacturers Association, 1992.

27. Vehicle Traffic Control Signal Heads, ITE Publication No. ST-017.



APPENDIX CSIGN DESIGN CHECKLIST



REQUIREMENTS AND REVIEWPROCEDURES FOR TRAFFICCONTROL SIGNAL DRAWINGS

Requirements

1. Signal drawings should be on Form PHM-125or similar form with CAD drawings preferred;

2. Preferred scale is 1:500 for rural intersectionsand 1:250 or 1:200 for urban intersections;

3. Title block with correct road names shouldbe above signature block;

4. Signature block should be on lower righthand side of the drawing and should bevisible when drawing is folded;

5. Correct HTA should be shown. Currently HTA144 (31) must be on the signature block;

6. The signature of the person designated toapprove the design under HTA 144 (31) isrequired on the drawing;

7. A north point is required;

8. Correct road names must be used as thedrawing may form a legal document. Thetitle block and body of the drawing mustagree;

9. A chart for listing revisions should be on thedrawing. Persons carrying out revisionsshould list them here and enter theirsignature and date on the revision;

10. A chart indicating equipment specificationssuch as mast arm lengths, mounting height,special heads, etc. is required;

11. A chart for special arrow heads should beused on drawings where such heads areused. If a chart is not on the drawing, a keyfor special heads must be shown;

12. All symbols used on the drawing must beindicated on a key chart.

13. Any signing that is critical to the traffic signaloperation i.e.: Left-turn signs adjacent to left-turn signal heads for fully protected left-turnlanes, overhead signing for dual left-turnlanes, active advance warning signs.

Review

1. Geometrics:

• should be acceptable for signal headplacement;

• drop curbs, etc. are identified, appropriatecurb radius shown;

• offset side roads are shown if part of signal;

• private entrances are shown if part of signal.Heads must be used;

• residential entrances. Note - these do notrequire signal heads but if they are used forcommercial purposes or rezoned tocommercial use or are for public use, headsmust be provided;

• a split entrance, two entrances each allowingan in and out movement on each side on thesame approach are not allowed to operatewithin the lateral curb lines of a signalizedintersection or intersection to be signalized;adequate pavement widths;

• left-turn lanes may not be opposite throughlanes;

• truck turning lanes should be adequate;

• median islands and channelized islands mustnot obstruct through lanes;



2. Zone Painting

• must be safe, may not create restricted orconflicting movements;

• should be legible, temporary drawings maybe exempted from zone painting scheme ifnot feasible to show paint during staging;

• stop lines and pedestrian crosswalks shouldbe indicated.

3. Equipment

• all signal heads and equipment under HTA;primary head is always recommended to be ahighway head with backboard;

• secondary head may be a standard headwith no backboard but preference is that ahighway head be used here also;

• all equipment must be standard as specifiedin the Ontario Traffic Manual and designmanuals;

• auxiliary heads may be added if required; e.g.visibility restrictions, curves, etc.;

• special heads must have correct numberindicated as per special arrow chart. If nochart, a key must be drawn showing the lensdisplay and lens sizes used;

• pedestrian heads must be indicated if used;

• push buttons are shown if pedestrianactuation is required. Arrows indicatingdirection of pedestrian pushbutton actuationare usually shown on the drawing.

4. Detection

• presence detection is indicated on the sideroad;

• presence detection is indicated in left-turnlanes if left turn phasing is required;

• long distance loops are used on the highway ifneeded to extend the amber display (safepassage);

• microwave, infrared and video detectors areused by various municipalities but presenceloops are preferred by most and are therecommended choice;

• microwave detectors can be useful for privatedriveways and temporary signals wherepermanent routes may not be possible orpavement is too poor to cut loops;

• emergency vehicle preemption detectors areshown facing the direction of travel in whichthey are utilized;

• railway preemption may be required if arailway crosses or is in close proximity to aproposed signalized intersection.

5. Phasing

• phasing appropriate to the design may beutilized;

• phasing should not create conflicting trafficmovements;

• phasing may never compromise the safety ofpedestrians;

• a phasing diagram is desirable on the signaldrawing especially at complex intersectionswhere multi-phasing may be required.



APPENDIX DLEGEND

Enquiries regarding the purchase and distribution of this manual should be directed to:

Publications Ontario

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Phone: 416.326.5300

Toll Free: 800.668.9938

TTY: 800.268.7095

Fax: 613.566.2234

Website: www.publications.gov.on.ca

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