Ministry of

Public Works

Transport

And Housing

Directorate

of Roads

ICTAAL (Instruction sur les Conditions Techniques d’Aménagement des Autoroutesde Liaison)

NATIONAL INSTRUCTION ON TECHNICALNATIONAL INSTRUCTION ON TECHNICALDESIGN REQUIREMENTS FOR RURALDESIGN REQUIREMENTS FOR RURALMOTORWAYSMOTORWAYS

CIRCULAR OF 12 DECEMBER 2000CIRCULAR OF 12 DECEMBER 2000

FACSIMILE ORIGINAL PAPER

Cover photo intentionally not included

Roads and Motorways engineering Department

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ICTAAL(Instruction sur les Conditions Techniques d’Aménagement des Autoroutes deLiaison)

NATIONAL INSTRUCTION ON TECHNICALDESIGN REQUIREMENTS FOR RURALMOTORWAYS

CIRCULAR OF 12 DECEMBER 2000

Roads and Motorways Engineering DepartmentCentre for Safety and Road Engineering

46, avenue Aristide Briand - BP 100 - 92225 Bagneux Cedex - FrancePhone: 33 1 46 11 31 - Fax: 33 1 46 11 31 69Website: http://www.setra.equipement.gouv.fr

This document was drawn up within the following work structure:

♦♦A Steering Committee, chaired by Jean-Pierre FORGERIT (General Council for Highways andCivil Engineering), with the following members:

• François-Daniel MIGEON, and subsequently D.R. (R./A.R.)• Christophe MASSON• Yves GASCOIN, and subsequently D.R. (R./C.A.)• Henri LOURDEAUX• Jean-Louis MIGNARD D.S.C.R. (S.R.)• Bernard LAFFARGUE SETRA• Jean-Marc SANGOUARD SETRA• Joël GILLON CETE du SUD-OUEST• Thierry LAGAT DDE de l’HERAULT• Bernard CATHELAIN SANEF• Jean-Michel GAMBARD SAPRR• Michel GUERIN COFIROUTE• Alain ROBILLARD ASF• Hubert MAGNON- PUJO SCETAUROUTE

♦♦A project team in charge of designing and preparing the document, led by Jean-MarcSANGOUARD (SETRA, Roads and Motorways Design Engineering Office), with the followingmembers:

• Lionel PATTE SETRA• Gilles ROUCHON SETRA• Christine MARCAILLOU SETRA• Christian GOURDEL DREIF• Jean-Claude BEGAULE CETE du SUD-OUEST• Bernard EDERT CETE RHONE-ALPES• Annie MEURIOT CETE de l’OUEST• Philippe RENIER DDE de SEINE-et-MARNE• Jean-Marie BRAUN INGEROP• Thierry CRESSON SETEC International• Max JALLEY SCETAUROUTE• Philippe BOIVIN SAPN• Philippe DE BECHEVEL SAPRR• Luc-Amaury GEORGE COFIROUTE• Jean-Pierre HAMANN SANEF• Michel LALLAU ASF

Lionel PATTE (SETRA, Roads and Motorways Design Engineering Office) was in charge of thetechnical secretariat of this project and drafting of the document

This document is French Government property and may not be used or reproduced,even partially, without permission from SETRA

© 2001 SETRA – Copyright 1st quarter 2001 - ISBN 2.11.091797-0Photo credit: Directorate of Roads

Designed and printed by Soregraph Levallois

Translation: Valerie JACOB ……….

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S r e

TABLE OF CONTENTS

♦♦CIRCULAR 4

♦♦FOREWORD 7

♦♦CHAPTER 1: GENERAL DESIGN 9

♦♦CHAPTER 2: VISIBILITY 13

♦♦CHAPTER 3: HORIZONTAL AND VERTICAL ALIGNMENT 17

♦♦CHAPTER 4: CROSS-SECTION 21

♦♦CHAPTER 5: INTERCHANGES 27

♦♦CHAPTER 6: RESTORATION OF COMMUNICATIONS 33

♦♦CHAPTER 7: FACILITIES AND USER SERVICES 35

♦♦CHAPTER 8: MOTORWAY SECTION IN DIFFICULT RELIEF 39

♦♦CHAPTER 9: CONVERTING A ROAD INTO A MOTORWAY 41

♦♦GLOSSARY 43

♦♦TABLE OF ABBREVIATIONS 49

♦♦TABLE OF NOTATIONS 50

♦♦BIBLIOGRAPHY 51

♦♦ANNEXES 55

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I R EMinistry of Public Works,Transport and Housing

________

Directorate of Roads________

Circular No. 2000 – 87 of 12 December 2000

amending theNational Instruction on Technical Design Requirements

for Rural Motorways of 22 October 1985(Instruction sur les Conditions Techniques d’Aménagement

des Autoroutes de Liaison - ICTAAL)NOR: EQUR0010213C

published in Official Gazette No. 24 of 10 January 2001

_____________

MINISTRY OF PUBLIC WORKS,TRANSPORT AND HOUSING

to

- Regional Prefects,- Regional Public Works Directorates- Civil Engineering Centres

- Département (County) Prefects,- County Public Works Directorates

- General Engineers in charge of co-ordinating General Regional Inspection Assignments,- General Engineers specializing in Roads,- General Engineers specializing in Engineering Structures,- President of the Motorway Concession Companies Control Assignment,- Director of the Roads and Motorways Engineering Department,- Director of the Centre for Studies on Road Networks, Transport, Urban Planning and Public

Construction,- Director of the Tunnel Engineering Centre,- Director of the Central Road Research Laboratory.

___________________

The national Instruction annexed to this circular supersedes and replaces the Instruction of 22October 1985 covering the national road network.

It must be applied for all interurban motorway projects, whether they cover new infrastructure orimprovements to existing roads. Within the meaning of this circular, motorways are roads withseparate carriageways, each with at least two lanes in their link sections, isolated from theirsurroundings and with grade-separated junctions.

C r c u l a r e

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Motorways in urban areas come under the National Instruction on Technical DesignRequirements for Urban Express roads (Instruction sur les Conditions Techniques d’Aménagementdes Voies Rapides Urbaines - ICTAVRU). Irrespective of their status, roads with separatecarriageways each having a single traffic lane and overtaking gaps, will be the subject of a futureInstruction.

It has proved necessary to update this ICTAAL Instruction on rural motorways not only toincorporate technical knowledge and developments that have been evolved since 1985 but also tobetter adapt motorways to their technical, environmental, socio-economic and financial contexts.Special rules have therefore been introduced for motorways with moderate traffic, motorway sectionsin difficult relief and for converting a road into a motorway.

This update makes better provision for user safety and comfort as regards self-explaining roaddesign, visibility conditions, and road facilities and equipment.

It retains the concise, synthetic form of the previous version and, for most of the specialtechnical characteristics and some functional characteristics, it refers to specific separate Instructions(such as those on traffic signs, safety barriers or cross-sections of non-standard engineeringstructures), guides or memos from the central technical departments, and - for its basic principles - toa supporting document.

It will be updated as required to ensure continued relevancy over the longer term.

This Instruction is applicable to projects not yet subjected to an approved preliminary designstudy. Other projects must be adapted to take account of these new rules provided this does not giverise to extra costs or significant delays.

With a view to making the road network consistent throughout the country, I invite you to informlocal and regional authorities of this Instruction so that those who wish to use it to prepare projectsunder their responsibility may do so.

For the Minister and by delegation

Director of Roads

Patrick GANDIL

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C r c u l a r e

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FOREWORD

♦SCOPE

This ICTAAL Instruction concerns the design of interurban motorways both for theconstruction of new infrastructure and improvements to the existing network. The termmotorway under this Instruction refers to a road with separate carriageways each with atleast two lanes in their link section, isolated from their surroundings and with grade-separated junctions.

This Instruction contains general principles and basic technical rules on this subject.Preliminary studies and detailed technical rules and recommendations are covered byspecific documents.

ICTAAL does not apply to:• other types of major roads such as single-carriageway roads with limited access

(express roads), interurban arterial roads and major roads, which are covered by aguide Aménagement des Routes Principales (ARP – major road design guide);

• roads with separate carriageways each with a single traffic lane and overtaking gaps,which will be covered by a future Instruction;

• motorways in urban areas, considered as urban express roads, which come underthe Instruction sur les Conditions Techniques d’Aménagement des Voies RapidesUrbaines – ICTAVRU - National Instruction on Technical Design Requirements forUrban Express Roads), including where these roads provide continuity or completionof an interurban motorway. However, in peri-urban areas, where the present or futurenature of the road is not very urban, it is advisable to apply the rules of the ICTAALInstruction.

Some of these rules may be granted derogations by ministerial decision.

♦STRUCTURE

This document contains nine chapters.

Chapter 1, on general design, describes how to adapt the project to its context.

Chapter 2 lays down visibility rules for all aspects of design.

The next three chapters describe the main geometric characteristics of the motorway:alignment (3), cross-section (4) and interchanges (5).

Chapters 6 and 7 give the principles for restoring communications and for facilities anduser services.

Chapters 8 and 9 give specific rules for motorway sections in difficult relief and forconverting a road into a motorway.

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é a m b u l e

P R E A M B U L E

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CHAPTER 1

GENERAL DESIGN

The first design stage is the choice of general characteristics: the road type whichdetermines the Instruction to be applied, the road category which determines the maingeometric characteristics of the alignment, the number of lanes, the synoptic pattern ofinterchanges and ancillary areas and, where applicable, the phased development of theproject.

These choices, some of which may have been made for previous studies, depend onthe project owner’s objectives for the function types and the level of service assigned to theroad. They require an overall approach and are based on preliminary studies that takeaccount of environmental constraints, socio-economic aspects and financial considerations.

♦1.1. FUNCTION OF THE MOTORWAY

Motorways link urban areas or regions, mainly over medium and long distances, andare an integral part of the European context. They offer users a high level of service in termsof safety, travel times, comfort and ancillary services.

♦ 1.2 CHOICE OF MOTORWAY CATEGORY

Motorways or motorway sections are classified in two categories differentiated by thelevel of their horizontal and vertical alignment characteristics. The choice of category is aconsequence of the environment in which the motorway lies (relief, land use, etc.). It must beconsistent with the perception the user has of it.

The categories are as follows:

• Category L1, suited to plains or valleys where relief constraints are moderate;

• Category L2, better suited to more difficult relief owing to the economic andenvironmental impacts involved.

These categories are appropriate to maximum permissible speeds of 130 and 110 km/hrespectively.

A motorway section passing through particularly difficult relief cannot be categorized and issubject to special rules set out in Chapter 8.

Consecutive sections in different categories must be at least ten kilometres long. The changeof category will occur at a change in the environment that is clearly perceptible by the user.Compliance with the rules for sequencing of alignment elements will ensure good conditionsfor a smooth transition.C o n c e p t o n g é n é r a l e

C O N C E P T I O N G E N E R A L E

C H A P I T R E 1

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♦♦1.3. DESIGNING THE MOTORWAY

1 1.3.1. TRAFFIC DETERMINING THE DESIGN

The motorway design – number of lanes in link section or on slip roads, number oftollgate lanes, ancillary areas – is determined:

• for "thirtieth hour" traffic. The hourly traffic levels indicated in the rest of thedocument are relevant to this definition. They are expressed in pcus in order tointegrate heavy traffic constraints;

• on the basis of traffic forecasts on opening the road and projected traffic trends,taking account of the effect of interlinking the network, with a view to optimizing theprovision of services in relation to costs.

1 1.3.2. MODERATELY TRAFFICKED MOTORWAY

A motorway is said to be moderately trafficked when, on opening, it carries an averagedaily traffic level of less than 10,000 v/d. This classification and any related adjustments,which are permissible up to a traffic level of 1,400 pcu/h in the direction of heaviest traffic(above this level, the motorway will receive normal characteristics), can be modulatedaccording to the motorway operating conditions.

1 1.3.3. CHOOSING THE NUMBER OF LANES

In the link section, the number of lanes per direction varies from two to four.

The hourly flow on the lane with the heaviest traffic must not exceed saturation flow,estimated at 1,800 pcu/h except, where applicable, in the case of occasional, or particularlyseasonal, peak traffic, if this will avoid adding another lane that is comparatively underusedin the intervening time.

♦♦ 1.4. SYNOPTIC PATTERN OF INTERCHANGES

Interchanges provide access to major centres or connect motorways to a nearby trunkroad. They are critical points that are costly to build and operate, particularly for closed tollsystems.

Owing to their socio-economic implications, it is important to justify their positioning anddate of construction, in relation with the development prospects of the regions given access,and to take account of the impact of their siting on the level of service of the roads theyinterlink.

The distance between two interchange points is usually around twenty kilometres. But itis normal for it to be shorter close to big cities, on crossings of densely populated regionsand in the case of conversion of an existing road, or for it to be longer in other contexts.

C H A P I T R E 1: C o n c e p t o n g é n é r a l e

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♦♦ 1.5. SYNOPTIC PATTERN OF ANCILLARY AREAS

The synoptic pattern of ancillary areas is determined by taking account of the structure of themotorway network.

The location, type and capacity of these areas must be consistent with the level and type oftraffic. The concern to optimize service to the user in terms of building and maintenancecosts may cause work to be deferred or partially executed, depending on foreseeable traffictrends.

♦♦ 1.6. STAGED CONSTRUCTION OF A MOTORWAY

The concern to keep project costs within a budget consistent with the services provided forthe user may result in staged construction of the motorway.

Over and above technical considerations, such as phased construction of pavementstructures and verges, interchanges or ancillary areas, the levels of traffic or financialconstraints may make it necessary to opt for transverse or longitudinal phasing.

1 1.6.1. TRANSVERSE PHASING

a) Motorways that can be widened

For dual two-lane motorways that can be widened to dual three-lane or even dual four-lane motorways, and for moderately-trafficked motorways, protective measures, such as landacquisition, clearance of rights-of-way, special earthworks or engineering structures, may betaken depending on the foreseeable date of widening the motorway and the conditions of thecorresponding work.

b) Localized construction in two transverse phases

In a very difficult area, for which the crossing is particularly costly (such as a non-standard bridge or a tunnel), it is feasible to build a single carriageway as the first stage,where justified by the socio-economic assessment.

To make the design more self-explaining for the user, this construction method requiresthe preparatory work for the second phase to be postponed, the work on the phased portionof motorway to be consistent with its operating method and the ends of this portion to betreated with the greatest care.

1 1.6.2. LONGITUDINAL PHASING

To maintain consistency and safety of a motorway link during the interim stages ofconstruction, it is important to build long enough, well-defined motorway sections, to limitareas of discontinuity and to treat temporary connections using very conspicuous facilities.

C H A P I T R E 1: C o n c e n g é n é r a l e

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♦♦ 1.7. CHANGE IN ROAD TYPE

A change in road type must only occur where there is a change in the function of theroad.

The transition from a motorway to another type of road must be made through a facilitydesigned to adapt the user’s behaviour and to coincide with a clearly perceptible change inthe environment, the use and the road design option.

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CHAPTER 2

VISIBILITY

High levels of safety and comfort require good visibility conditions enabling the driver toanticipate events occurring on the motorway.

♦♦ 2.1. CONVENTIONAL MEASURES

1 2.1.1. SPEEDS

To account for the speeds actually travelled by motorists, the speed V85 is conventionallyused, which is levelled off to the maximum permissible speed V85

é.

1 2.1.2. OBSERVATION POINT

This is the eye of the driver of a light vehicle, situated at a height of one metre above theground and a distance of two metres from the right side of his lane.

1 2.1.3. OBSERVED POINT

The following visibility rules state the nature and position of the observed point. Wherethis concerns a vehicle, the observed point is the most effortlessly perceived of the two rearlights, situated at a height of 0.6 metres above the ground and at a distance of 1 metre and2.5 metres respectively from the right side of the lane in question.

♦♦ 2.2. VISIBILITY RULES

1 2.2.1. VISIBILITY IN THE LINK SECTION

The sight distance to be targeted is the total stopping distance da (see Annex 1) from therear of a vehicle at a standstill on its lane.

But design constraints do not enable this objective to be met under all circumstances.Nevertheless, an overall study incorporating this visibility requirement at an early designstage will reduce the number and importance of such situations.

However this total stopping distance must be ensured at approaches to points or areasthat present a particular risk of slowing or tailbacks: reduction in the number of lanes, accesspoints, toll plazas, non-standard engineering structures, tunnels, etc.

1 2.2.2. VISIBILITY AT APPROACHES TO ACCESS POINTS

At the approach to any motorway access point – whether an interchange or an ancillaryarea - , the driver must be able to decide to change direction and make the necessarymanoeuvres.i s b

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a) Visibility at a motorway exit

The manoeuvering distance dms at the exit is defined as the distance travelled at aconstant speed V85

é for the time taken to implement the manoeuvre, fixed at 6 seconds.

For the two right-most traffic lines, at the distance dms from the “earliest point of exit” (S =1.50 m), (see fig. 2.1.), the driver must perceive:

• the entire face of the advance traffic sign placed at this point;

• the marker warning of the approach nose, which is assumed to be observed at aheight of 1 m, at the place where the nose is 5 m wide.

Figure 2-1: Visibility rule at a motorway exit

d ms =6 V Nose marker

m 5,00 D31

S=1,50m

h=1,00 m

b) Visibility at a motorway entry

The sight distance for the right-hand lane of the motorway must at least be equal to thetotal stopping distance from the rear of an entering vehicle positioned on the entry slip roadat the “earliest point of entry” (E=1.00 m).

Figure 2-2: Visibility rule at a motorway entry

E=1,00 m

h=0,60 m

da

1 2.2.3. VISIBILITY IN AN INTERCHANGE

A driver travelling on an interchange must have the following distances ahead:

• along each slip road, the total stopping distance from the rear of a vehicle at astandstill on his lane;

• at the approach to a bend, a sight distance from the markings limiting his lane atthe beginning of the circular arc, at least equal to the distance travelled at aconstant speed V85

é in 3 seconds, to enable him to perceive the curve and adapthis behaviour in time;

• at the approach to, and level with, the junctions connecting to an ordinary road,visibility conditions meeting the recommendations for at-grade junctions, taking intoaccount the speeds travelled on the slip road.I T R E 2: Vi s b l t é

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1 2.2.4. VISIBILITY OF AN EMERGENCY LAY-BY

Emergency lay-bys are situated so that, on approaching them, they will provide a sightdistance for the right-hand motorway lane, at least equal to the total stopping distance fromthe rear of a vehicle assumed to be in the middle of the lay-by.

1 2.2.5. VISIBILITY OF AN ARRESTER BED

On the right-hand lane or, where relevant, on the slow-moving traffic lane, a lorry driver,viewing at a height of 2.50 m and at a distance of 2.50 m from the edge of the carriageway,must be able to see the beginning of the checkered marking from at least a distance of 170 m.

1 2.2.6. VISIBILITY IN UNDERGROUND STRUCTURES

The visibility rules are given by the Tunnel Guidebook.

♦♦ 2.3. CHECKING VISIBILITY RULES

Because of the high travelling speeds on a motorway, visibility rules involve long sightdistances. The geometric design rules given in the following chapters do not necessarilyguarantee compliance, which means that they must be examined and checked.

It is usually possible to comply with visibility rules by ensuring that the horizontalalignment, vertical alignment and positioning of critical points (such as access points or tollplazas) are co-ordinated and by adapting the treatment of verges or the central reserve(distance from slopes in cut sections, positioning of equipment, height of plantations, etc.).

When this is the case, an interruption of visibility of a given point for less than twoseconds is acceptable.

Where it is nonetheless impossible to comply with visibility rules, a localized reduction inthe maximum permissible speed is possible, provided the treatment of the road and itsenvironment permit clear perception by the user.

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CHAPTER 3

HORIZONTAL AND VERTICAL ALIGNMENTCHAPTER 3

Design rules for the horizontal and vertical alignment are intended to ensure goodconditions of safety and comfort appropriate to each motorway category.

It is possible to dissociate the two carriageways either by their vertical alignment or theirhorizontal alignment, if this will save costs or better integrate them into their surroundings.

♦♦3.1. HORIZONTAL ALIGNMENT

1 3.1.1. RADIUS VALUES

Horizontal radii must comply with the minimum values in Table 3-1.

Table 3-1: Minimum values of horizontal alignment radii

Motorway category L1 L2

Minimum radius (Rm) 600 m 400 m

Minimum non-superelevated radius (Rnd) 1 000 m 650 m

It is recommended to replace long straight reaches by large-radius curves.

To improve comfort and facilitate compliance with visibility rules, the use of radii equal toor greater than 1.5 Rnd is advisable provided this does not entail significant extra costs.

1 3.1.2. SEQUENCING OF HORIZONTAL ALIGNMENT ELEMENTS

Circular curves of moderate radius (<1.5 Rnd) may only be used if the following horizontalalignment sequencing rules are followed:

• Introduce such curves over a distance of 500 to 1,000 m using larger-radiuscurves. In this case, two successive curves must meet the following requirement:R1≤1.5R2, where R1 is the radius of the first curve encountered and R2(<1.5Rnd) isthat of the second curve. This recommendation is mandatory in a risk section, suchas after a long downhill slope, at the approach to an interchange or an ancillaryarea, or in an area subject to black ice.

• Separate two successive curves by a straight reach of at least 200 m, except fortwo curves in opposite directions introduced by progressive transition curves.

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a c é e n p l a n e t p r o f l e n l o n g

1 3.1.3. PROGRESSIVE TRANSITION CURVES

Curves with a radius of less than 1.5 Rnd are introduced by progressive transition curves(clothoids).

Their length is at least equal to the greater of the following two values: 14 |∆δ| and R/9;where R is the radius of curvature (in m) and ∆δ the difference in crossfalls (in %) of theconnected alignment elements.

♦♦ 3.2. VERTICAL ALIGNMENT

The reference line of a motorway vertical alignment is conventionally the axis of theroadway if the central reserve is surfaced or, if not, the axis of the left-hand edges of thecarriageways.

An embanked vertical alignment appropriate for earthworks, pavement construction, andfor maintaining natural runoff is preferable to a vertical alignment level with the ground,unless it is difficult to integrate it into the surroundings.

1 3.2.1. LIMIT VALUES

Vertical alignment parameters must comply with the limit values given in Table 3-2.

Table 3-2: Limit values of vertical alignment parameters

Motorway category L1 L2

Maximum gradient 5 % 6 %

Minimum radius of crest curves 12 500 m 6 000 m

Minimum radius of sag curves 4 200 m 3 000 m

It is recommended to use radii greater than the minimum radii where this will not greatlyincrease the cost.

1 3.2.2. SECTIONS WITH BIG DIFFERENCES IN LEVEL

Geometric configurations that generate big differences in level are liable to pose safetyand capacity problems. An appropriate alignment and specific signing will limit the risks. Butsome configurations may also require an additional lane for slow-moving vehicles, or anarrester bed. (see 7.1.5.).

C H A P I T R E 3: a c é e n p l a n e t p r o f l e n l o n g H A P I T R E 2: Vi s b l té

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a) Alignment

To encourage users, particularly lorry drivers, to adopt behaviour consistent with thedifficulties incurred by big differences in level, it is essential to:

• exclude long straight reaches and long curves, and to prefer short straight reachesassociated with radii close to 1.5 Rnd;

• provide a transition zone before each descending gradient, by means of aprogressive reduction in the horizontal alignment radii, for example;

• introduce a steep slope outright but avoid gradually increasing slopes;

• not incorporate a more moderate slope in the midst of a steep slope (greater than4%) (see fig. 3.1.);

• avoid introducing critical points (interchanges, ancillary areas, curves with radiismaller than Rnd, etc.) in the gradient and in the hectometres that follow it.

Figure 3-1: More moderate slope in the midst of a steep slope – an example of aconfiguration to be excluded

b) Slow-moving traffic lane

The advisability of a slow-moving traffic lane will be considered according to the trafficlevels. This additional lane is not normally necessary for motorways with more than two lanesper carriageway, or those with moderate traffic.

On ascending gradients, it is recommended to provide a slow-moving traffic lane wherethe length and gradient are such that the speed of slow-moving vehicles is reduced to lessthan 50 km/h over a minimum distance of 500 m. The slow-moving traffic lane will thenextend over the entire section in which the speed of the slow-moving vehicles remains below50 km/h.

On descending gradients, the difference in level ∆ of the section in which there is a slopegreater than 3%1 will be adopted as the risk indicator. It is recommended to provide a slow-moving traffic lane where ∆ exceeds 130 m. Repeated descending gradients over shortintervals below the breaking efficiency recovery time, may justify this lane for a value of∆ shorter than 130 m. A slow-moving traffic lane must begin slightly before the descendinggradient in question.

A slow-moving traffic lane may not be interrupted. However, at the bottom of the slope itis possible to shorten this lane if it will avoid a non-standard bridge or a tunnel.C H A P I T RE 3: T a c é e n p l a n e t p r o f l e n l o n g1 Short intermediate stretches with a slope of less than 3% do not interrupt the section and are to be included in the calculation ofthe difference in level of the section.

Steep slope Moderate slope Steep slope

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♦♦ 3.3. CO-ORDINATION OF THE HORIZONTAL AND VERTICALALIGNMENT

An overall study must be made of the co-ordination of the horizontal and verticalalignment to ensure proper integration into the surroundings, compliance with visibility rulesand as far as possible, a degree of visual comfort. The following measures will help toachieve these objectives:

• Associate a concave vertical alignment, even slightly concave, with a horizontalradius including a large side clearance;

• Make the horizontal and vertical curves coincide, then comply with the requirement:Rvertical > 6Rhorizontal to avoid imperfect inflexion;

• Eliminate loss of alignment visibility provided this does not greatly increase thecost. Where this cannot be avoided, the carriageway must reappear at a distanceat least 500 m ahead, which creates a sufficiently unambiguous loss of alignmentvisibility to prevent a misleading perception.

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CHAPTER 4

CROSS SECTIONC H A P R E: T a c é e n p l a n e t p r o f l e n l o n g

♦♦ 4.1. CROSS-SECTION IN THE LINK SECTION

Figure 4-1: Cross-section components in the link section

carriageway

carriagewayay

B.D.G B.D.G

T.P.C..C.vel reserveC

B.A.U B.A.U berm

verge verge

berm

Central strip

Usable width

roadway

Usable width

T.P.C = central reserve ;B.A.U = hard shoulder for emergency use ; BDG = left hard strip

1 4.1.1. CARRIAGEWAY

Each carriageway has 2 to 4 lanes, each 3,50 m wide.

1 4.1.2. CENTRAL RESERVE

The central reserve provides the physical separation between two directions of trafficflow. Its width is the result of the width of its constituents, which are the two left hard stripsand the central strip.

a) Left hard strip

This hard strip is designed to allow slight swerving off-course and to prevent a wall effectdue to the safety barriers. In left-hand curves, it facilitates compliance with visibility rules.

It is free of any obstacles, surfaced and connected to the carriageway without anydifference in level. It is one metre wide.

b) Central strip

This strip physically separates the two directions of traffic flow. It can receive specificequipment (safety barriers, sign supports, runoff collection and drainage structures) andwhere necessary, bridge piers and landscaping elements.

Its width will at least depend on the equipment it carries.

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If it is less than or equal to 3 metres wide, it will be stabilized and surfaced to facilitatemaintenance. If not, it can be grassed and planted with shrubs, unless its width and the sitetopography enable the natural ground and existing vegetation to be preserved. In this case, a1-metre wide berm is maintained at the edge of the left hard strip.

c) Central reserve gap

These gaps will enable any necessary transfer of traffic from one carriageway to theother.

They are situated on either side of non-standard bridges, tunnels and interchanges andhave a maximum spacing of 3 km.

1 4.1.3. VERGE

The verge includes a hard shoulder bordered on the far side by a berm.

a) Safety zone

The width of the safety zone from the edge of the carriageway is 10 m for motorwaycategory L1 and 8.50 m for category L2. In cut, the safety zone does not exceed a height of 3m.

Figure 4-2: Safety zone in cut.

In the safety zone, all the following aggressive devices must be isolated, if not excluded:

• obstacles such as trees, poles, masonry, direction sign supports, rock walls orengineering structure supports;

• uncovered drainage channels;

• ditches more than 50 cm deep, unless their slopes are less than 25%;

• slopes in cut sections or berms with slopes exceeding 70%;

• embankments more than 4 m high, with slopes exceeding 25%, or more than 1 mhigh where there is a sudden difference in level.

b) Hard shoulder for emergency use

The hard shoulder facilitates emergency stopping off the carriageway, recovery of aswerving vehicle, the avoidance of an object on the carriageway, and intervention of theemergency, maintenance and field operation services.

Safety zone

10 / 8,50 m

3,00 m

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It consists of an extra carriageway width extending from the geometric edge of thecarriageway, which bears the edge marking, then an area free of any obstacles that issurfaced and able to receive a heavy parked vehicle. There must be no difference in levelbetween the carriageway and the hard shoulder.

Its width is 2.50 m, or 3.00 m where HGV traffic exceeds 2,000 v/d (both directions takentogether).

c) The berm

The berm helps to provide visual clearance and carries road equipment such as safetybarriers or traffic signs.

Its width, which will depend mainly on the space required for the functioning of the safetybarrier to be installed, is at least 1 metre. But the berm can also be included in a drainagesystem with a slope not exceeding 25%.

♦♦4.2. CROSS-SECTION IN A LINK SECTION OF A MODERATELY-TRAFFICKED MOTORWAY

For a moderately-trafficked motorway, the cross-section can be adjusted by:

• reducing the overall width of the left hard strip and the left-hand lane to 4 m, bypreferably narrowing the left-hand lane rather than the left hard strip;

• replacing the hard shoulder by a right hard strip, 2 m wide and surfaced over 1 m.

♦♦4.3 CROSS-SECTIONS OF STANDARD ENGINEERINGSTRUCTURES

On any standard engineering structure, the traffic lanes, hard shoulder and left hard stripshave the same width as the link section.

For an overhead pass, the choice of the structure type (number, position and width of thepiers) requires the impact of this structure on the cross-sectional elements to be taken intoaccount. The structure must have a height clearance of 4.75 m at all points of the usablewidth of the motorway. It must also have an additional height allowance, usually 0.10 m, topermit subsequent resurfacing of the carriageway. The height clearance of a light structure(footbridge, sign gantry, etc.) is increased by 0.50 m.

C H A P I T R E 4: P r o f l e n t r a v e r s

24

♦♦4.4. SPECIAL LOCALIZED CROSS-SECTIONS

1 4.4.1. NARROWED CROSS-SECTION IN THE LINK SECTION

If for various reasons (such as economic conditions, inadequate right-of-way or extensiveearthworks), a normal design is not possible, a narrower cross-section can be used locally.

The reduction in the cross-section components must apply strictly to those areas in whichit is made necessary by special constraints, unless this causes overfrequent changes. Avoidcombining a narrow cross-section with a bendy alignment or a steep descending gradient.

The following cross-section adjustments will be considered:

1. reducing the overall width of the left hard strip and the left-hand lane to 4 m,preferably by narrowing the left-hand lane rather than the left hard strip;

2. replacing the hard shoulder by a right hard strip, 2.00 m wide, surfaced over1.00 m.

1 4.4.2. NARROW CROSS-SECTION ACROSS A STANDARD ENGINEERINGSTRUCTURE

The cross-section across a standard engineering structure is reduced in the same way asin a link section.

1 4.4.3. NARROW CROSS-SECTION ACROSS A NON-STANDARD BRIDGE

The choice of cross-section across a non-standard bridge is guided by the specificcircumstances (occasional worksites, structure maintenance, accidents, etc.) and acomparison of costs and services to the user. The minimum usable width to be provided perdirection of traffic flow is given below:

Moderately-trafficked dual two-lane motorway 8,75 m

Dual two-lane motorway 9,75 m

Dual three-lane motorway 14,00 m

1 4.4.4. CROSS-SECTION ACROSS AN UNDERGROUND STRUCTURE

The cross-section across an underground structure is given by the Tunnel Guidebook.

1 4.4.5. SLOW-MOVING TRAFFIC LANE

This lane, which is 3.5 m wide, is bordered on the right by a hard strip surfaced over awidth of 1 m, with emergency lay-bys every kilometre.

At the beginning of the lane, there will be a 130-m long transitional widening zone to theright. The end of the slow-moving lane is shown by a change in road marking, which ensurescontinuity of the right-hand land. The ending transition of the left-hand lane begins at least200 m after the end of the slow-moving traffic lane, according to § 4.5.

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t r a v e r s♦♦ 4.5. CHANGE IN CROSS-SECTION

1 4.5.1. TRANSVERSE DEFLECTION

If a change in cross-section results in transverse deflection of the carriageway, it ispreferable to locate it in a curve of the horizontal alignment. Failing this, the slope on theinitial carriageway axis must not exceed 2%.

1 4.5.2. CREATION OF AN ADDITIONAL LANE (WIDENING TRANSITION)

Whether the additional lane is added on the left side or the right side of the carriageway,it is essential to ensure continuity of the right-hand lane and to comply with the 130-mwidening transition zone.

Figure 4-3: Schematic diagram of a widening transition zone

130 m

1 4.5.3. LANE REDUCTION TRANSITION

Lane reduction transition zones are to be dissociated from entry and exit manoeuveringareas (interchanges and ancillary areas).

It is the left-hand lane that ends. There are two configurations for ending of the lanedepending on the side of the lane reduction. Reduction from the right side is simpler andoften sufficient (see fig. 4.4). But reduction from the left side, which requires a taperingsystem into the initial profile (see fig. 4.5), is necessary in some cases, particularly to taperinto a two-way carriageway.Figure 4-4: Schematic diagram for lane reduction without a tapering system

L/2 Li

Figure 4-5: Schematic diagram for lane reduction with a tapering system

L/2 Li Lr

where L is the advance warning distance (see notation table)

Table 4-1: Merging lengths Li and tapering lengths Lr depending on the road category

Motorway category L1 L2

Merging length Li 470 m 310 m

Tapering length Lr 250 m 200 m

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♦♦ 4.6. CROSSFALLS

Curves with a radius of less than Rnd slope towards the inside of the curve.

1 4.6.1. ON STRAIGHT REACHES AND NON SUPERELEVATED CURVES

The crossfall is 2.5% towards the outside of the carriageway.The slope of a hard shoulder (or a right hard strip) is the same as that of the adjacent

carriageway, but beyond the extra width of the carriageway bearing the edge marking, it maybe increased to 4% for technical reasons.

The slope of a left hard strip and a central reserve roof-type slope are the same as that ofthe adjacent carriageway.

The external berm has a crossfall of 8% that can be increased to 25% if it is included in adrainage system.

1 4.6.2. ON SUPERLEVATED CURVES

The crossfall of a carriageway varies linearly as a function of 1/R, between 2.5% for Rnd

and 7% for Rm.

The slope of the hard shoulder (or the right hard strip) on the inside of the curve is thesame as the slope of the adjacent carriageway. The slope of the hard shoulder (or the righthard strip) on the outside of the curve remains the same as on a straight reach, provided theslope of the superelevation does not exceed 4%. Above this, it is in the opposite direction tothe superelevation and equal to 1.5%, except for the extra carriageway width whichmaintains the same slope as the carriageway.

The measures for the other roadway components are the same as in § 4.6.1.

1 4.6.3. CHANGE IN SUPERELEVATION

The change in superelevation is usually linear along the progressive transition curve.

a) Superelevation rotation point

Where the central reserve is surfaced, the superelevation rotation point is usually situatedon the roadway axis. If not, the superelevation rotation point of each carriageway is situatedon the left edge of the carriageway.

b) Surface water drainage

When it proves necessary to make a change in the superelevation, the length of thecarriageway over which the superelevations of between -1% and +1% extend, is determinedso that it will not be detrimental to surface water drainage or to the appearance of thealignment.

In the area of change of superelevation, drainage of surface water on the carriagewayrequires a resultant gradient of 0.5% at all points on the carriageway.

In superelevated curves, the central reserve has facilities to drain away the surface waterfrom the farside carriageway.

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CHAPTER 5

INTERCHANGESH A P I T R E 4: P r o f l e n t r a v e r s

Grade separated interchanges between motorways are not the same as grade separatedinterchanges between a motorway and an ordinary road.

♦♦ 5.1. GRADE-SEPARATED INTERCHANGES BETWEENMOTORWAYS

The configuration of this interchange andthe geometric characteristics of its branchesresult primarily from the amounts of traffic inthe streams.A traffic stream of more than 800 pcu/hjustifies two traffic lanes for the branchconcerned.Where two distinctly dissymmetrical streamsmerge together, the branch carrying thesecondary stream merges into the branchcarrying the main stream or branches off tothe right. This rule is for guidance only if thetraffic is moderate on the section commonto both branches.

1 5.1.1. CHARACTERISTICS OF A ONE-LANE BRANCH

A one-lane branch is designed in the same way as an interchange slip road except whereit continues a motorway section – case of a straight-ahead lane or a dedicated traffic lane.

1 5.1.2. CHARACTERISTICS OF A TWO-LANE BRANCH

a) Horizontal and vertical alignment

A two-lane branch is a direct or semi-direct configuration but never a loop configuration.

As a general rule, the rules for motorway category L2 are to be followed. If necessary, radiismaller than the minimum values of this category can be adopted but they must not be belowthe following values suitable for a maximum permissible speed of 90 km/h:

minimum radius (Rm) 240 m

..radius of crest curves 2700 m

radius of sag curves 1900 m

The straight reach separating two successive curves in the same direction can be reducedto 100 m.

Secondary stream

Main stream

Secondary stream

Main stream

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b) Cross-section

The rules given in Chapter 4 for the link section apply.

c) Divergence of two traffic flows (exit)The exiting system depends on the amount of diverging traffic. Below 1,800 pcu/h, it does

not give rise to the ending of a mainstream lane (see fig. 5.1.), but above this level, amainstream lane will end (see fig. 5.2.). However, the latter configuration is inadvisable on anascending gradient owing to the conflicts resulting from lane changes imposed on slow-moving vehicles.

Figure 5-1: Exit system over two lanes without ending of the mainstream lane

Figure 5-2: Exit system over two lanes with ending of the mainstream lane

d) Convergence of two flows (entry)

The method of treating the junction depends on the traffic in the converging flows, thenumber of lanes in the feeder branch and the targeted level of service. It is either by amerging lane or an additional lane.

Any excess lanes are reduced downstream of the converging nose in accordance with4.5.3.

♦♦5.2. GRADE-SEPARATED INTERCHANGES BETWEEN AMOTORWAY AND AN ORDINARY ROAD

1 5.2.1. CHOICE OF INTERCHANGE TYPE

Choice of the interchange type is based on the required traffic transfers, traffic intensity,operating system and site configuration.

A grade-separated roundabout type of interchange is not recommended, particularly inthe upper position, owing to the safety problems entailed. Where it cannot be avoided, takemajor precautions, particularly as regards the perception of the roundabout circle, the users’mutual perceptions and any aggressive devices.

1 5.2.2. HORIZONTAL ALIGNMENT OF A SLIP ROAD

An exit slip road or a slip road carrying a two-lane traffic flow cannot have a loop configuration.

C H A P I T R E 5: É c h a n g e u r s

29

a) Limit values of radii

A horizontal radius is conventionally measured at the inside edge of the carriageway.

The minimum radius is 40 m. But except for loops, the radius of the first curveencountered at the exit must be at least 100 m.

In a loop, it is not recommended to use radii exceeding 60 m.

The minimum non superelevated radius (Rnd) is 300 m.

b) Sequencing of horizontal alignment elements

A loop comprises a single circular arc with clothoid arcs at each end.

Two successive arcs in opposite directions must meet the following requirement: R1≤2R2, where R1 and R2 are the radii of the first and second curves encountered.

c) Progressive transition curve

A circular curve has a clothoid arcs at each end, with lengths equal to the greater of thetwo values: 6R0.4 and 7 |∆δ|; where R is the radius of curvature (in m), and ∆δ the differencein superelevation (in %) of the linked alignment elements.

These are minimum values but it is not advisable to use higher values as they may makeit more difficult for the user to estimate the final curvature.

1 5.2.3. VERTICAL ALIGNMENT OF A SLIP ROAD

The limit values of the vertical alignment parameters are as follows:

maximum gradient 6 %

.. minimum radius of crest curves 1 500 m

minimum radius of sag curves 800 m

At the junction with the ordinary road, it is possible to use smaller radii over shortstretches.

1 5.2.4. CROSS-SECTION OF A SLIP ROAD

The carriageway is bordered on either side by a hard strip that has the same structure asthe carriageway, and by a berm that can be integrated into the drainage system.

The widths of the cross-section components are as follows:

Carriageway OnewayTwo-way

3,50 m7,00 m

Right hard strip 1,00 m

Left hard strip 0,50 m

30

In a curve with a radius smaller than 100 m, an extra width of 50/R per lane must beadded.

Where justified by specific requirements, the verge can be designed with a usable widthof 6 m.

A section of roadway carrying traffic flows in opposite directions usually has a two-waycarriageway. Appropriate systems designed to separate the two directions of traffic flow(safety barriers, etc.) must be used for a configuration that may otherwise be a potential forwrong way movements.

Along the slip roads, the width of the safety zone is 4 m.

1 5.2.5. CROSSFALL OF A SLIP ROAD

The profile of a two-way carriageway consists of two plane surfaces connected to the axis,that of a one-way carriageway consists of a single plane surface. The hard strips have thesame crossfall as the adjacent lane.

Outside the superelevated curves, the crossfall on one side is 2.5% towards the right. Insuperelevated curves, the slope varies linearly in relation to 1/R between 2.5% for the radiusRnd (300 m) and 7% for 100 m, and remains at 7% below 100 m.

1 5.2.6. CONNECTION TO THE MOTORWAY

The merging of a slip road onto the motorway is made at the entry by a merging lane andat the exit by a deceleration lane.

The entry arrangement is successively:

• a merging section whose obliquity with the motorway axis is between 3% and 5%.Its length, which depends on the radius of the last curve of the slip road (see fig.5.5) must enable the conventional speed of 55 km/h to be reached at point “E =1.00 m”, with progressive acceleration of 1 m/s2;

• a manoeuvering section adjacent to the motorway carriageway, 200 m long and3.50m wide;

• a taper, 75 m long.

Figure 5-3: Motorway entry arrangement

E=1,00m

3,50m 200m

manœuvering section taper acceleration section

75m

C H A P I T R E 5: É c h a n g e u r s

31

The exit arrangement is successively:

• a manoeuvering section, which is a 150 m long taper adjacent to the motorway, asfar as the point where the diverging nose attains a width of 1 m;

• a deceleration section, the length of which enables speed to be reduced from theconventional speed at the end of the manoeuvering section (70 km/h, for a sliproad radius smaller than120 m) to the speed appropriate for the radius of the firstcurve encountered (see fig. 5.5 and Annex 2), with progressive deceleration of 1.5m/s2.

Figure 5-4: motorway exit arrangement

150 m manœuvering section deceleration

section

1,00 m

Figure 5-5: Progressive deceleration/acceleration lengths Lo as a function of the radius of thefirst/last slip road curve.

The length of sloping deceleration oracceleration section is given by theformula:

Ld/a = Lo/(1-10.p)

where p is the gradient as an algebraicvalue.

1 5.2.7. JUNCTION CONNECTING TO AN ORDINARY ROAD

A junction connecting to an ordinary road is to be treated according to therecommendations for at-grade junctions.

They should be designed (geometry, equipment, etc.) to deter wrong-way movements up sliproads. For this purpose, roundabouts are preferable to ordinary at-grade junctions.

Figure 5-6: Example of geometry that will deter wrong way movements.

0

10

20

30

40

50

60

70

80

90

40 50 60 70 80 90 100 110 120

Rayon de la courbe (m)

L0 (m

)

Longueur de décélération Longueur d'accélérationDeceleration length Acceleration length

Curve Radius (m)

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♦♦ 5.3. DISTANCE BETWEEN TWO MOTORWAY ACCESS POINTS

The distance between two access points – calculated between the earliest entry point(E=1.00 m) of one access and the earliest exit point (S=1.50 m) of the next – must be longerthan 1,200 m.

Failing this, the interchange movements are made by a weaving lane or, for an interval ofless than 500 m, by a collector road. A weaving lane more than 750 m long is not advisableand an interval of between 750 m and 1,200 m long is to be avoided.

33

CHAPTER 6

RESTORATION OF COMMUNICATIONSC H A P I T R E 5: É c h a n g e u r s

The restoration of communications concerns roads, main services and naturalmovements (such as waterways or wildlife passages) severed by the motorway. Owing to itscost, this work should be limited and grouped where possible.

♦♦6.1. ROADS

1 6.1.1. NATIONAL ROADS

A national road is restored in accordance with current Technical Instructions, taking intoaccount its planned long-term development.

1 6.1.2. OTHER ROADS

Geometric restoration characteristics are determined in consultation with the localauthority concerned. They must be consistent with the characteristics of the link section. Inparticular, a restoration width exceeding the width of the existing carriageway should notadopted except to integrate local authority requirements.

♦♦6.2. MAIN SERVICES

The project to restore each network (railway, waterway, electricity or telecommunicationssystems) is determined after consulting the managers concerned.

♦♦6.3. NATURAL MOVEMENTS

These are restored in accordance with the conclusion of the project environmental impactstudy.

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35

CHAPTER 7

FACILITIES AND USERS SERVICES

♦♦7.1. SAFETY AND OPERATING FACILITIES

The need to conduct specific studies for these facilities at the same time as the alignmentstudies is explained by the close interdependence of the geometry and the facilities.

1 7.1.1. SAFETY BARRIERS

An overall study providing for the presence of barriers should be conducted in order to:

• meet service constraints and maintenance and operating requirements;

• take specific users, such as motorcyclists or pedestrians, into account;

• define the optimum configuration of the roadside (slopes, drainage systems, etc.).The design of the berm must enable the most suitable systems to be installed.

a) On the central reserve

Safety barriers systematically equip the central reserve. The choice of the type of barrierwill depend on: traffic volume and mix, the risk to be covered (obstacle, difference in level,etc.), visibility and operating constraints, and the width of the central reserve.

b) On the verge

On dual three-lane or four-lane carriageways, safety barriers must be installedsystematically.

On dual two-lane motorways, safety barriers are installed in the presence of aggressiveequipment situated in the safety zone defined in 4.1.3.a, and on the outside of curves with aradius smaller than 1.5 Rnd.

In addition, barriers suitable for HGV restraint are installed in places where theconsequences of running off the road are particularly serious due to nearby sensitivefacilities (such as drinking water collection areas or fuel tank farms), housing or publicfacilities, or because of the configuration of projects (viaducts, high embankments) or thetype of right-of-way bordered or crossed (railway, heavily-trafficked road).

1 7.1.2. TRAFFIC SIGNS AND MARKING

The study of road marking or traffic signs, whether fixed or dynamic (e.g. VMS) mustparticularly concern critical points such as interchanges, ancillary areas, or changes in cross-section).q u p e m e n t c e s à l ’ u s a g e r

ÉQUIPEMENTS and SERVICES À L’USAGER

C H A P I T R E 7

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1 7.1.3. ANTI-GLARE DEVICES

In horizontal curves, the central strip may be equipped with devices to prevent glare fromheadlights, provided visibility rules are met.

1 7.1.4. EMERGENCY LAY-BYS AND EMERGENCY ROADSIDE PHONES

Emergency lay-bys are provided every 2 km and, in the absence of hard shoulders, everykm. In addition, an emergency lay-by is provided on either side of tunnels and non-standardbridges.

An emergency phone is installed in each emergency lay-by and ancillary area.

Figure 7-1: Geometric characteristics of emergency lay-bys:

in the presence of a hard shoulder for emergency use

30 m 32 m 12 m

4,00 m P.A.U.

Hard shoulder

in the absence of a hard shoulder for emergency use

30 m 32 m 32 m

4,00 m P.A.U.

Hard strip

1 7.1.5. ARRESTER BEDS

Provision of an arrester bed must be examined separately from the slow-moving trafficlane.

An arrester bed is recommended upstream of a critical point (such as an interchange,non-standard bridge or tunnel) situated on a descending gradient, after a difference in level∆ (see 3.2.2) greater than 130 m.

Its location and design must facilitate its use: good visibility conditions both of the arresterbed and the critical point, mound at end of bed, specific signing.

1 7.1.6. FENCING

The installation and type of the fencing must be appropriate to the protectionrequirements and must not be detrimental to the motorway landscaping.

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A P I T R E 7: É q u p e m e n t s e t s e l ’ u s a g e r

1 7.1.7. PUBLIC LIGHTING

Lighting is only necessary at toll plazas and in tunnels. It may also be advisable where amotorway crosses or borders an area with lighting liable to hamper traffic on the motorway(activity area, airport, etc.).

♦♦7.2. FIXED OPERATING FACILITIES

1 7.2.1. TOLL AREAS

Toll areas consist of a gradual widening of the carriageways up to the full widthaccommodating the toll lanes.

The length of the dividing islands varies between 30 and 45 m depending on theoperating system. A full roadway width extends for a minimum distance of 5 m on either sideof the islands.

In the vicinity of the islands, the vertical alignment becomes less steep as the gradientmust not exceed 1.5% over 40 m on either side of the toll plaza axis, and 2.5% up to 80 m.

Toll plaza design is based on the traffic flow in the toll lanes and on the toll system(open/closed) and the operating system (automatic, manual, electronic toll collection) of thetoll lanes.

Sufficiently large parking areas, offering adequate services to users, are provided closeto the toll plazas.

1 7.2.2. MAINTENANCE AND OPERATION CENTRES

The level of service to users requires specific maintenance and operation centres to beprovided. They may be introduced progressively as the traffic increases.

1 7.2.3. OPERATIONAL AND EMERGENCY SERVICE ACCESS

The positioning of operational and emergency service access linking to the ordinary roadnetwork is determined according to the requirements of the relevant services.

♦♦7.3. ENVIRONMENTAL FACILITIES

1 7.3.1. COLLECTION AND DRAINAGE OF SURFACE WATER

Water-related regulatory requirements are to be taken into account when designing thealignment, with a view to defining the collection, drainage, and possibly storage andtreatment facilities of surface water.

C H A P I T R E 7: É q u p e m e n t s e t s e s à l ’ u s a g e r

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1 7.3.2. ARCHITECTURAL AND LANDSCAPE TREATMENT

Architectural and landscape treatment has an aesthetic objective in relation with the areacrossed, and a functional objective (such as slope stabilization, cultural and touristinformation, traffic guidance or glare prevention).

It concerns not only engineering structures, ancillary areas, toll plazas, maintenance andoperating centres, acoustic protection and fences but also ground surface patterns andplantations, with a view to creating an overall composition that mutually enhances themotorway and the landscape.

1 7.3.3. ACOUSTIC EQUIPMENT

Noise-related regulatory requirements are to be taken into account when designing thealignment in order to limit passive protection devices such as screens, berms or frontinginsulation.

♦♦7.4. ANCILLARY AREAS

A distinction is made between rest areas for users to park, rest and relax, service areaswhich also have permanent fuel distribution facilities, and parking areas at the toll plazas.These areas may provide additional services relevant to their functions.

As soon as the road is opened, it must provide a rest area at least every 30 km and aservice area every 60 km. However, on a moderately-trafficked or toll-free motorway, theintegration of appropriately signposted services in the overall plan of such areas situated atthe toll plazas or off the motorway may enable them to be more widely spaced.

An ancillary area may be associated with an interchange insofar as the entry and exit sliproads do not cross this area.

An ancillary area on one side of the motorway but accessible to users from bothdirections of traffic flow is particularly appropriate for a moderately-trafficked motorway.

It may be a good idea to provide an ancillary area at a beauty spot, particularly to limitrisks of inappropriate stopping on the hard shoulder.

The design of entries to and exits from these areas must follow the rules given in Chapter5.

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CHAPTER 8

MOTORWAY SECTION IN DIFFICULT RELIEF

A P I T R E 7: É q u p e m e n t s e t s e à l ’ u s a g e r

This is a section of a motorway in category L2, for which the relief presents difficultiessuch that systematic compliance with the rules for this category would result in inordinatecosts. This can only apply to a motorway section where the difficulties – mainly inmountainous regions – are continuous or frequent over at least ten kilometres.

The rules for category L2 apply except for the following adjustments.

♦♦8.1. GENERAL DESIGN

When a motorway has to be adapted to its surrounding environment, this results in anoverall decline in the level of service. The maximum permissible speed for a section indifficult relief is accordingly 90 km/h.

A section in difficult relief, more than any other, requires consistent treatment and aspecial study of the following points:

• integration into natural landscapes which tend to be sensitive areas of scenicinterest;

• the consequences of the geometric design in terms of geotechnics, hydrology anddrainage;

• the consequences of the design and facilities (safety barriers, traffic guidanceequipment, etc.) on the maintenance and operating conditions of the motorway(natural hazard management, winter service, drainage etc.).

This section will be introduced at a sharp change in relief (pass, constriction, gorge)perceptible by the user.

♦♦ 8.2. SPECIAL REQUIREMENTS

1 8.2.1. VISIBILITY

The reduction in maximum permissible speed correlatively limits the constraints given inChapter 2.

S e c t o n d ’ a u t o r o u t e n r e l e f d ff c l e

SECTION D’AUTOROUTE EN RELIEF DIFFICILE

C H A P I T R E 8

40

1 8.2.2. HORIZONTAL ALIGNMENT

Only the minimum superelevated radius (Rm) is reduced to 240 m.

The rules for the sequencing of alignment elements given in Chapter 3 are essential andmust be applied for radii smaller than Rnd, particularly for the transition to an upstreamsection in another category.

The use of small radii (R<1.5 Rm) requires excellent self-explaining design of the curve.

1 8.2.3. PROGRESSIVE TRANSITION CURVE

Curves with a radius greater than Rnd do not need to be introduced by a progressivetransition curve.

Where the introduction of a progressive transition curve creates difficulties, it can beshortened as necessary down to a length of 8.4 |∆δ|.

Furthermore, in a reverse curve, the superelevation may vary linearly over the entirecurve between the two connected circular arcs.

1 8.2.4. VERTICAL ALIGNMENT

The minimum values of the radii are as follows:

Minimum radius of crest curves 2 700 m

Minimum radius of sag curves 1 900 m

1 8.2.5. CO-ORDINATION OF HORIZONTAL AND VERTICAL ALIGNMENT

This must primarily seek to comply with visibility rules and facilitate the generalperception of the alignment, by aiming for consistency of the horizontal alignment, thevertical alignment and the general site topography.

1 8.2.6. CROSS-SECTION

The width of the safety zone is reduced to 7 m.

1 8.2.7. INTERCHANGES BETWEEN A MOTORWAY AND AN ORDINARYROAD

In an interchange loop, where necessary, it is possible to reduce the horizontal radius to30 m.

The length of the exit taper may be reduced to 110 m.

1 8.2.8. ANCILLARY AREAS

The distance between ancillary areas may be adapted to take into account heavyinstallation constraints.

41

MOTORWAY SECTION IN DIFFICULT RELIEFCHAPTER 9

CONVERTING A ROAD INTO A MOTORWAY

This chapter concerns the conversion of an existing single or dual carriageway road intoa motorway, also known as “in situ development”.

It requires a favourable situation (relief, land use, geometry of the already-existing road).It involves a socio-economic study to compare it with a project for a new motorwayalignment, particularly in the case of a project to convert a dual carriageway road.

♦♦9.1. GENERAL PRINCIPLES

1 9.1.1. APPLICABLE RULES

The conversion project must comply with the rules given in the previous chapters for newmotorways.

However, systematic compliance with these rules may incur deterrent costs and only befeasible as a medium or long term objective. The decision for components of the existingroad is thus to be based on a safety diagnosis. Section 9.2. gives the special measures thatcan be implemented.

A study must be made of the re-use of existing road components, such as engineeringstructures or pavements.

1 9.1.2. RESTORATION OF COMMUNICATIONS

Appropriate alternative routing must be provided for traffic that cannot use the convertedroad.

Motorway operating requirements and worksites to install or repair networks and facilitiesjustify moving them out of the motorway right-of-way.

1 9.1.3. USER FACILITIES AND SERVICES

The level of service of a motorway requires specific organization for road operation andmaintenance and overall rehabilitation of user facilities and services.

T a n s f o r a t o n d ’ u n e r o u t e n a u t o r o u t e

TRANSFORMATION D’UNE ROUTE EN AUTOROUTE

C H A P I T R E 9

42

♦♦9.2. SPECIAL MEASURES

1 9.2.1. HORIZONTAL AND VERTICAL ALIGNMENT

To meet the often heavy constraints generated by the existing alignment, the concept ofthe motorway category, which mainly concerns driving comfort, can be made more flexible:successive sections shorter than 10 km long in different categories are permissible providedthis will not give rise to excessive re-shaping, which would make the alignment tooheterogeneous.

Whatever the case, the limit values of motorway category L2 must always be met, exceptfor a section in difficult relief.

Between two successive curves not introduced by progressive transition curves, astraight reach of 100 m may be sufficient.

The correction of a transition between alignment elements is only justified for a special-hazard curve.

Insofar as good conditions of visibility and perception are provided, the principles of co-ordinating the horizontal and vertical alignments alone do not justify changing the existingalignment.

1 9.2.2. CROSS-SECTION

a) Cross-section in link section

Where the cost of bringing the cross-section into line with standards would be particularlyhigh, the following are permissible:

• a hard shoulder 2.50 m wide, even if HGV traffic exceeds 2,000 v/d;

• limiting the overall width of the left-hand lane and the left hard strip to 4 m.

b) Cross-section across an engineering structure

An existing engineering structure can be maintained if it has a usable width of 8.50 m perdirection.

c) Crossfall

In a curve, a change will only be required if the present slope is more than one pointlower than the recommended superelevation.

1 9.2.3. INTERCHANGES

The existing geometry can be maintained provided it offers a satisfactory level of serviceand does not present any obvious hazard. However, deceleration and merging arrangementsmust comply.

1 9.2.4. ANCILLARY AREAS

Ancillary areas may be provided off the motorway, close to an interchange.

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A P I T R E 9: T a n s f o r a t o n d ’ u n e r o u t e n a u t o r o u t e

GLOSSARYThis glossary defines and explains the main terms and phrases used in this guide relating

to motorway design.

It does not aim to be exhaustive but primarily to remove any lexical ambiguity. It gives themeanings as used in this document, and a few neologisms and special meanings. Forexplanations of technical terms relating to other technical fields such as the environment,road operation, safety or engineering structures, refer to the domain-specific glossaries (seebibliography).

Additional lane Motorway entry configuration in which the lanes downstream of theconverging nose of two branches are added on to the carriageway.² � Merging lane.

E=1.00m

Area, ancillary Area close to the major roadway set aside to provide specificservices to users or operators.

Area, rest Ancillary area set aside for users to park, rest and relax.

Area, service Rest area including a permanent service station and usually offeringshopping facilities.

Berm Non-usable side part of the verge (sometimes the central reserve),bordering a hard shoulder or a hard strip and usually grassed.

Branch fromintersection

Any branching of a motorway interchange.

Branch, direct Easy configuration in which the branch does not cross the motorwayfrom which it leads off.

Direct branches

semi-direct branch

Loop branch

Branch, loop Constraining loop-shaped configuration, requiring a change ofdirection of around 270° by vehicles.

44

Branch, semi-direct Configuration in which the branch crosses the motorway (overpassor underpass) from which it leads off. It includes a curve and areverse curve.

Carriageway(geometric)

That part of the road constructed for use by vehicular traffic. It doesnot include structural extra widths carrying the edge marking.

Central reserve Strip separating two carriageways on the same roadway. It consistsof a central strip and two left hard strips.

Central reserve gap Area of the central reserve, with the same structure as thecarriageway, enabling traffic to be taken across from onecarriageway to the other, where necessary. It is equipped withsafety barriers that can be removed quickly by the field services.

Collector In an interchange, an auxiliary collateral lane, separated from themain carriageway by a dividing strip, which receives traffic flowsfrom the (merging) slip road and from the (exiting) main arterialroad, and then reallocates them. It enables the weaving traffic flowsto be transferred outside the main carriageways. ² Syn. collector ²≠ weaving lane

auxiliary lane

collector

Central reserve

physical separation

Deflection 1• Deviation of the outer edge of the carriageway because of achange in cross-section (e.g. width of central reserve, lanecreation).

2• (misuse) measurement of inflection associated with this deviation.

Distance, exitmanoeuvering

Conventional distance required at the approach to an exit to enablethe driver to decide to change direction and make the necessarymanoeuvres. ² Notation: dms.

Distance, totalstopping

Theoretical conventional distance required for a vehicle to stop inrelation to its speed, calculated as the sum of the braking distanceand the distance travelled during the perception-reaction time.Notation: da. ² See Annex 1.

Emergency lay-by Area set aside on the verge to facilitate local conditions foremergency stopping.

Engineering structure,non-standard

This definition is given by the Circulars of 5 May 1994 and 27October 1987, which are the French Instructions for national roadsand concession motorways respectively. Here the definition isrestricted to a bridge or viaduct termed “non-standard” because ofits length.

45

Engineering structure,standard

Any bridge or viaduct not consistent with the definition of a non-standard engineering structure.

Hard shoulder (foremergency use)

A surfaced part of the verge, adjacent to the carriageway, free ofany obstacles, designed to enable emergency stopping of vehiclesoff the carriageway. ² Note: It includes the structural extra width ofthe carriageway.

Interchange, grade-separated

Junction at which traffic transfers are separated from one anotherand made to take place outside the main arterial roads. ² Genericterm covering grade-separated interchanges between motorways,and between motorways and ordinary roads. ² Syn.

Interchange, grade-separated (betweenmotorways)

An interchange that allows the passage from one motorway toanother.

Interchange, grade-separated(motorway/ordinaryroad)

Grade-separated interchange between a motorway and the ordinaryroad network.

Interchange, grade-separated roundabout

Interchange with a single, grade-separated circular carriageway withwhich slip roads link up (� diamond interchange, doubleroundabout).

Junction, grade-separated

See interchange

Junction, transition In an interchange, an at-grade junction where one or more sliproads from the motorway link up with the ordinary road.

Lane reductiontransition

Arrangement for the gradual ending of a side lane.

Lane, diverging Collateral lane enabling exiting vehicles to slow down outside themain traffic flow.

Lane, mainstream See flow, straight-through

Lane, merging Collateral lane enabling vehicles entering a motorway to merge intothe straight-ahead traffic stream.

Lane, slow-movingtraffic

Additional side lane provided on steep ascending or descendinggradients for use by the slowest-moving vehicles.

Lane, weaving Additional side lane on a main carriageway designed to link up asuccessive, closely situated entry and exit, and facilitate weaving ofentering or exiting traffic streams at the same time.

weaving lane

T.P.C.

Link section Section of the main arterial road situated away from critical pointssuch as interchanges, non-standard engineering structures orunderground structures.

46

Motorway Road with separate carriageways, each with at least two lanes perdirection in the link section, systematically with grade-separatedjunctions, without frontage access. ² In practice, the technicalmotorway object covered by this guide does not necessarily havemotorway status within the meaning of the French Road Act, (Art.L122 and R122), and vice versa. ² Syn. Type L road. ² See ARP

Motorway in difficultrelief

1• Motorway for which the relief presents major, continuousdifficulties, such that systematic compliance with the rules for theother categories would give rise to excessive costs. 2• By ext.ranking of these sections.

Motorway, moderatelytrafficked

See traffic, moderate

Nose Extremity of an island situated at the converging or divergingseparation of two traffic lanes in the same direction. ² Note: not tobe confused with its marker.

pcu (abbreviation ofpassenger car unit)

Passenger car equivalence that takes account of the obstructiongenerated by traffic congestion from various vehicle categoriesthrough the application of equivalence coefficients.

Phasing, longitudinal Staged construction method. Longitudinal progression of thebuilding or improvement of a road, causing sections to be openedsuccessively.

Phasing, transverse 1• Staged construction method. Practice consisting in deferring theconstruction of cross-sectional components of a road (e.g.carriageway, traffic lanes), causing the road to be opened in aninterim phase. 2• By ext. Any subsequent planned or unplannedconstruction of further cross-sectional components.

Point E = 1.00 m Portion of the cross-section where the converging nose attains awidth of 1 m. ² Syn. “earliest entry point”.

Point S = 1.50 m Portion of the cross-section where exit taper attains a width of 1.50m. ² Syn. “earliest exit point”.

Radius, minimum(notation Rm)

Ellipt. and misuse. Absolute minimum radius of the cross-section. ²Note: It is associated with a maximum slope of the carriagewaytowards the inside.

Radius, minimum non-superelevated

Radius below which the carriageway is sloped towards the inside ofthe curve. Ellipt. Non-superelevated radius. ² Notation Rnd.

Restoration ofcommunications

1• Re-establishing any means of communication, such as a road,main services, or natural movements, severed by the motorway. 2•By ext.: structure, or arrangement that is the result of this action(e.g. overpass, wildlife crossing).

“Road” Spec. A level major road not isolated from its surroundings, with asingle carriageway. ² See Catalogue of interurban road types; ARP

47

Reverse curve Curve with two circular arcs in opposite directions connected by twotangent clothoid arcs.

Road category Subdivision of a road type, which mainly determines the geometriccharacteristics of the alignment. A category is identified by the lettercorresponding to the road type, followed by a code number (e.g.: L1,L2, T100, R80).

Road restraint system See safety barrier.

Road type Set of characteristics organized into a whole, which makes adistinction between road families that give importance to similarfunctions. Its distinguishing characteristics are the surroundings, thetypes of junction and the number of carriageways. ² � Roadcategory. ² See Catalogue of interurban road types; ARP

Road with limitedaccess (singlecarriageway)

Main, grade-separated, single-carriageway road. ² Syn. road, typeT. In practice, the road with limited access as a technical objectdoes not always have the status of an express road. Conversely,many dual-carriageway roads have the status of an express road. ²See Catalogue of interurban road types; ARP

Road, grade-separated Ellipt. Road with junctions that are systematically grade-separated,without frontage access on the main section. ² Syn. Road isolatedfrom its surroundings. ² ant. level road, ordinary road. ² SeeMotorway; Road, type T.

Road, major Road with the characteristics of a trunk road on the scale of thenational road network or département (county) road networks. Itusually carries a daily traffic level of more than 1,500 vehicles. ²See ARP

Road, trunk Dual-carriageway major road, not isolated from its surroundings,with at-grade junctions (that do not cross the central reserve). ²See Catalogue of interurban road types; ARP

Roadway Part of the infrastructure consisting of the carriageway orcarriageways, verges and, where appropriate, the central reserve. Itdoes not include the rounded surfaces connecting to ditches andslopes.

Safety barrier In accordance with the terminology of European Standard NF EN1317-2 and French Standard NF P 98-409, all systems designed tolimit the consequences of running off the road by keeping vehicleson the usable part of the road or by stopping them. ² Syn. Roadrestraint systems

Safety zone Side strip adjacent to the carriageway, extending over the verge andbeyond, free of any obstacles liable to worsen the consequences ofa vehicle accidentally going off the road.

Self-explaining roaddesign

Ability of a road or motorway and its surroundings, through all theircomponents, to give any user an accurate, quickly understoodpicture of the type of infrastructure and its surroundings, its uses,the probable or possible movements of other users, and thebehaviour expected of this user.

48

Slip road 1• usually. Road providing a transition between a motorway andanother road.

2• spec. Id. in an interchange.

Slip road, loop Similar to a loop branch, it is a constraining loop-shapedconfiguration requiring a change of direction of around 180° byvehicles.

Staged development Practice consisting in phasing the building or improvement of amotorway so as to defer investment and enable the motorway to beopened in the meantime. ² Syn. phased development ² Seephasing, longitudinal; phasing, transverse.

Strip, central Non-usable part of the central reserve between the two left hardstrips.

Strip, hard Strip alongside the carriageway, stabilized, surfaced or unsurfacedand free of any obstacles. It carries the edge marking.

Strip, left hard Hard strip to the left of a one-way carriageway.

Strip, right hard Hard strip to the right of the carriageway.

“Thirtieth hour” 1• “Thirtieth hour” traffic. Ellipt. Thirtieth of the annual hourly flows indecreasing order. 2• Time corresponding to this flow.

Toll gate All toll lanes positioned transversely to the motorway axis, whichintercept all traffic in both directions.

Toll lane Passage on a traffic lane set aside for toll collection facilities.

Toll plaza All related toll collection facilities on a given site.

Toll, closed system A toll system consisting of plazas with toll gates or on interchanges,which intercepts all traffic and controls all incoming and outgoingvehicles. The amount collected at the exit corresponds to thejourney stage and the vehicle class.

Toll, open system A toll system consisting of plazas with toll gates or on interchanges,which intercepts all traffic at one or more points along the route tocollect the same amount for each category of vehicles, whatevertheir origin or destination.

Traffic stream 1• Traffic movement from the entering direction to the exitingdirection of a transfer interchange. ² Syn. Traffic flow/traffic. 2•Straight-ahead stream. Continuous movement along the same axis.

Traffic upon opening Stabilized (or almost stabilized) traffic observed on a new orconverted motorway after the traffic build-up period, usually lasting afew months after the road is opened.

Traffic, moderate,(moderately-traffickedmotorway)

Temporary state of a motorway with a traffic level of less than10,000 v/d upon opening and at a point considered to be less than1,400 pcus at the “thirtieth hour’ in each direction of traffic flow. Thisconcept can be varied according to operating constraints.

49

Usable width Width of the stabilized part of a roadway, comprising thecarriageway, the hard shoulder or the right hard strip, and the lefthard strip.

V85 Conventional speed below which 85% of vehicles travel under free-flowing traffic conditions (free-moving vehicles).

Verge Side portion of the roadway bordering a carriageway.

Weaving See lane, weaving

Widening transitionzone

Arrangement to create an extra lane (� deceleration lane).

l o s a

50

r e

o s a r e

ABBREVATIONS

ARP Aménagement des Routes Principales (Design of Major Roads)

ICTAAL Instruction sur les Conditions Techniques d’Aménagement des Autoroutes deLiaison (National Instruction on Technical Design Requirements for RuralMotorways)

ICTAVRU Instruction sur les Conditions Techniques d’Aménagement des Voies RapidesUrbaines (National Instruction on Technical Design Requirements for UrbanExpress roads)

VMS Variable message sign

AADT Average annual daily traffic (both directions taken together)

pcu passenger car unit

51

NOTES TABLETA B L E D E S A B R É V I AT I O N S

da Total stopping distance

dms Exit manoeuvering distance

L Advance warning distance, parameter for designing road marking (see InterministerialInstruction on Road Marking – Book 1 – Part 7)

Lo Level section acceleration / deceleration length

L1 First motorway category

L2 Second motorway category

Li Merging length of an ending traffic lane

Lr Reduction transition length for an ending lane with deflection of the inside edge of thecarriageway

Rm Minimum radius

Rnd Minimum non-superelevated radius

V85 Speed below which 85% of free-moving vehicles travel (see Glossary)

V85é V85 levelled off at the maximum permissible speed

52

BIBLIOGRAPHY

♦♦GENERAL DOCUMENTS

• Accord européen du 15 novembre 1975 sur les grandes routes de trafic international(A.G.R.)(European agreement of 15 November 1975 on main international traffic arteries [A.G.R.])

• Décret n° 84-164 du 2 mars 1984 portant publication de l'accord européen du 15novembre 1975. (J.O. du 09.03.1984)(Order No. 84-164 of 2 March 1984 announcing the European agreement of 15 November1975. (Official Journal of 09.03.1984)).

• Circulaire du 17 octobre 1986 relative au dimensionnement de la hauteur des ouvragesd'art routier sur le réseau national (J.O. du 31.12.1986)(Circular of 17 October 1986 on the design of road engineering structure height in thenational road network. (Official Journal of 31.12.1986)).

• Circulaire du 20 août 1987 relative aux modalités de mise en oeuvre du repérage desitinéraires AGR.(Circular of 20 August 1987 on methods of implementing the landmarking of AGR routes.)

• Circulaire DR du 27 octobre 1987 relative à l'instruction des dossiers techniquesconcernant la construction et l'aménagement des autoroutes concédées.(DR Circular of 27 October 1987 on the examination of technical documents for the buildingand improvement of concession motorways.)

• Code la voirie routière – Loi n° 89-413 fu 22 juin 1989. (J.O. du 24.06.1989)(Road Act No. 89-413 of 22 June 1989. (Official Journal of 24.06.1989)).

• Décret 89-89-631 du 4 septembre 1989. (J.O. du 08.09.1989)(Order 89-631 of 4 September 1989. (Official Journal of 08.09.1989).)

• Catalogue des types de routes en milieu urbain – Circulaire du 9 décembre 1991 –S.E.T.R.A. – 1991 (réf. B9241).(Catalogue of interurban road types – Circular of 9 December 1991 – S.E.T.R.A. – 1991 (ref.B9241)).

• Instruction sur les Conditions Techniques d'Aménagement des Voies RapidesUrbaines, I.C.T.A.V.R.U., CETUR, 1990. (Actualisation du chapitre 3 – 1998)(Instruction sur les Conditions Techniques d'Aménagement des Voies Rapides Urbaines,ICTAVRU (National Instruction on technical design requirements for urban express roads),CETUR, 1990. [Update of Chapter 3 – 1998]).

53

• Circulaire du 5 mai 1994 définissant les modalités d'élaboration, d'instruction etd'approbation des opérations d'investissements sur le réseau routier national non concédé –SETRA – 1994 (réf. E9459).(Circular of 5 May 1994 defining methods for preparing, examining and approving investmentoperations on the nonconcession national road network – SETRA – 1994 (ref. E9459)).

• Aménagement des Routes Principales (A.R.P.) – Circulaire du 5 août 1994 modifiantl'instruction sur les conditions techniques d'aménagement des routes nationales(I.C.T.A.R.N.) – SETRA – 1994 (réf. B9668)(Aménagement des Routes Principales, ARP (Design of Major Roads) – Circular of 5 August1994 amending the Instruction sur les conditions techniques d'aménagement des routesnationales, I.C.T.A.R.N. (National Instruction on technical design requirements of nationalroads) – SETRA – 1994 (ref. B9668).

• Méthodes d'évaluation économique des investissements routiers en rase campagne –Circulaire n° 98-99 du 20 octobre 1998 – D.R. – 1998.(Economic evaluation methods of rural road investments – Circular No.98-99 of 20 October1998 – D.R. – 1998).

• La documentation des techniques routières françaises (cédérom DTRF) – Répertoire debase 2000 – SETRA 6 2000 (réf. DTRF 0008).(French road engineering documentation (DTRF CD-Rom) – 2000 basic directory – SETRA –2000 (ref. DTRF 0008)).B l o g r a p h eB I♦♦GEOMETRY

• Implantation des voies supplémentaires en rampe sur infrastructure à 2x2 voies – Noted'information n° 21 (Série économie – Environnement – Conception ) – S.E.T.R.A. – 1989

(réf B8941)Adding extra lanes on ascending gradients of dual two-lane carriageway roads –

Information Memo No. 21 (Economy – Environment – Design series) – S.E.T.R.A. – 1989(ref. B8941).

• Circulaire DR du 11 janvier 1993 relative à la mise aux normes autoroutières desL.A.C.R.A. à 2x2 voies.

DR Circular of 11 January 1993 on the upgrading to motorways of existing dual two-lanecarriageways ensuring continuity of the motorway network.

• Descente de forte pente et de grande longueur sur les routes de type "autoroute"- Noted'information n° 52 (série économie – environnement- conception) – SETRA- 1997

(réf. B9707)Long, steep descending gradients on “motorway” type roads” – Information Memo No. 52

(Economy – Environment – Design series ) – SETRA – 1997 (ref. B9707).

•Aménagement des carrefours interurbains – Carrefours plans- S.E.T.R.A. – 1998(réf. B9836) Improving interurban intersections - At-grade junctions – S.E.T.R.A. – 1998 (ref. B9836).

54

♦♦ENGINEERING STRUCTURES AND TUNNELS

• Dossier pilote des tunnels – C.E.T.U. - 1990Tunnel Guide – C.E.T.U. – 1990.

• Circulaire DR du 29 août 1991 relative aux profils en travers des ouvrages d'art noncourants.

DR Circular of 29 August 1991 on cross-sections of non-standard engineeringstructures.

♦♦RESTORATION OF COMMUNICATIONS

• Passage pour la grande faune – guide technique – SETRA – 1993 (réf. B9350).Large wildlife crossings – Technical Guide – SETRA – 1993 (ref. B9350).

♦♦FACILITIES AND TRAFFIC SIGNS

• Arrêté du 24 novembre 1967, modifié, relatif à la signalisation des routes et autoroutes.(J.O. du 07.03.1968).

Order of 24 November 1967, amended, on road and motorway traffic signs. (OfficialJournal of 07.03.1968).

• Instruction interministérielle sur la signalisation routière – Livre I. (J.O. réf. 5346).Interministerial Instruction on traffic signs – Book I. (Official Journal ref. 5346).

• Garde-corps, glissières, corniches, grilles:CG 77 – Dossier pilote – SETRA – 1977 (réimpression 1997). (réf. F9709).

Bridge rails, fences, cornices, grids: GC 77 – Guide Document – SETRA – 1977 (reprint1997). (ref. F9709).

• Circulaire DR 82-31 de mars 1982 relative à la signalisation de direction. Fasciculespécial B.O. n° 82- 14).

DR Circular 82-31 of March 1982 on direction signs. Special issue Official Gazette No.82-14).

• Lettre circulaire DR /DSCR 85-280 du 29 août 1985 relaitive à la signalisation dedirection sur le réseau autoroutier.

DR/DSCR Circular letter 85-280 of 29 August 1985 on direction signs on the motorwaynetwork.

• Instruction relative à l'agrément et aux conditions d'emploi des dispositifs de retenuedes véhicules contre les sorties accidentelles de chaussé – Circulaire 88-49 du 9 mai 1988–(Direction des J.O., B.O. du 19.06.98, n° 17 p 13 à 14).

National Instruction on approval and conditions of use of road restraint systems toprevent vehicles accidentally going off the road – Circular 88-49 of 9 May 1988 – (OfficialJournal Dept., Official Gazette of 19.06.98, No. 17 p 13 to 14).

• Circulaire DSCR 95-13 du 6 janvier 1995 relative à la signalisation de direction sur lesautoroutes et routes express( B.O. du 20.03.1995 n° 7).

DSCR Circular 95-13 of 6 January 1995 on direction signs of motorways and expressroads (Official Gazette of 20.03.1995 No.7).

55

• Implantation des postes d'appel d'urgence – Guide technique – S.E.T.R.A. – 1996(réf. E9678).Installing emergency roadside phones – Technical Guide – S.E.T.R.A. – 1996 (ref.

E9678).

• Norme NF P 98-409 Barrière de sécurité – Critères de performance, de classification etde qualification – 1998.

Standard NF P 98-409 Road safety barriers – Performance, classification andqualification criteria – 1998.

• Norme NF EN 1317 – 2 Dispositifs de retenue routiers – Partie 2.Standard NF EN 1317 – 2 Road restraint systems – Part 2.

• L'équipement des routes interurbaines – Volumes 1 et 2 – SETRA- 1998 (réf. E9851). Equipment for interurban roads – Volumes 1 & 2 – SETRA – 1998 (ref. E9851).

• Allègement de la signalisation de police aux entrées et sorties d'autoroutes – relevé dedecisions de la reunion du 15 mars 1999 – DSCR; R/CA; SETRA.

Reduction of police signs at motorway entries and exits – record of decisions of themeeting on 15 March 1999 – DSCR; R/CA; SETRA.

• Circulaire n° 99 –68 du 1er octobre 199 relative aux conditions d'emploi des dispositifsde retenue adaptés aux motocyclistes.

Circular No. 99-68 of 1 October 1999 on conditions of use of road restraint systemsappropriate for motorcyclists.

♦♦ DRAINAGE

• Loi n° 92-3 du 3 janvier 1992 sur l'eau et décrets d'application. ( J.O. du 04.01.1992).Act No. 92-3 of 3 January 1992 on water, and implementing orders. (Official Journal of

04.01.1992).

• L'eau et la route – Volume 7: Dispositifs de traitement des eaux pluviales – SETRA –1997(réf. B9741).

Water and the Highway – Volume 7: Rainwater treatment systems – SETRA – 1997 (ref. B9741).

• Guide technique de l'Assainissement Routier [GTAR] – à paraître.Road drainage technical guide [GTAR] – S.E.T.RA – forthcoming.

♦♦ LANDSCAPE TREATMENT

• La végétalisation – Outil d'aménagement – Guide technique – CETE de Lyon; CETEMéditerranée – SETRA – 1994(réf. B9418).

Greening – Landscaping tool – Technical Guide – CETE de Lyon; CETE Méditerranée –SETRA – 1994 (ref. B9418).

• Route et paysage – guide méthodologique – S.E.T.R.A – 1995 (réf.B9545).Roads and the landscape – Methodological Guide – S.E.T.RA. – 1995 (ref. B9545).

56

♦♦ACOUSTIC PROTECTION

• Conception et réalisation des écrans acoustiques. 3 volumes – C.E.T.U.R. - 1985(Design and construction of noise screens. 3 volumes – C.E.T.U.R – 1985.)

B l g r a p h e• Loi 92-1444 du 31 décembre 1992 relative à la lutte contre le bruit. (J.O. du 01.01.93,

B.O. n° 1 du 20.01.93). Act 92-1444 of 31 December 1992 on noise control (Official Journal of 01.01.93, Official

Gazette No.1 of 20.01.93).• Décret 95-22 du 9 janvier 1995 relatif à la limitation du bruit des infrastructures

routières. J.O. du 10.05.95, B.O. du 20.01.95).( Order 95-22 of 9 January 1995 on reduction of road infrastructure noise. (Official

Journal of 10.01.95, Official Gazette of 20.01.95)).

• Arrêté du 5 mai 1995 relatif au bruit des infrastructures routières. (J.O. du 10.05.95,B.O. n° 13 du 20.05.95).

Order of 5 May 1995 on road infrastructure noise. (Official Journal of 10.05.95, OfficialGazette No.13 of 20.05.95).

• Circulaire du 12 décembre 1997 relative à la prise en compte du bruit dans laconstruction de routes nouvelles ou l'aménagement de routes existantes du réseau national.(NOR EQUR 9701908C).

DR Circular of 12 December 1997 on taking account of noise in the building of new roadsor the improvement of existing roads in the national network (NOR: EQUR 9701908C).

• Calcul prévisionnel du bruit routier: paramètres de traffic sur routes et autoroutesinterurbaines – Note d'information n°54 (Série économie- environnement – conception) –S.E.T.R.A. – 1998 (réf. B9804).

Predicting road noise: traffic parameters on interurban roads and motorways –Information Memo No. 54 (Economy – Environment – Design series) – S.E.T.R.A. – 1998(ref. B9804).

• Bruit et etudes routières , manuel du chef de projet – S.E.T.R.A. ; C.E.R.T.U. – àparaître.

Noise and road studies, Project Manager’s handbook. – S.E.T.R.A; C.E.R.T.U. –forthcoming.

♦♦SAFETY

• Sécurité des routes et des rues – SETRA; CETUR – 1992 (réf.E9228).Safety of roads and streets – SETRA; CETUR – 1992 (ref. E9228).

♦♦WEBSITE

• http://www.setra.equipement.gouv.fr

57

ANNEXES♦♦ANNEX 1: VISIBILITY

a) Total stopping distance (da)

The total stopping distance consists of the braking distance, which is the distancetravelled during the braking action, and which reduces speed from V to 0 in conventionalconditions (conditions of tyres and wet carriageway), increased by the distance travelledduring the perception-reaction time (taken to be 2 seconds)da = V²/2g (γ(V) + p) + 2V, where:

- V is in m/s;- γ(V) is the mean deceleration expressed as a fraction of g. It is a function of V (see Table A-1);- p is the gradient, as an algebraic value.

b) Summary of the main sight distances

Table A-1: Main sight distances (m) and mean deceleration value (γ(V)) in an emergencybraking situation, as a function of the speed.Speed (km/h) 50 70 90 110 130

Mean deceleration (as a fraction of g) γ(V) 0,46 0,44 0,40 0,36 0,32

Total stopping distance on a levelsection (p=0)

da 50 85 130 195 280

Exit manoeuvering distance dms(6.V) 85 120 150 185 220

(values rounded up to 5 m)

♦♦ANNEX 2: CONVENTIONAL SPEED ON A SLIP ROAD

Figure A-1: Conventional speed on a slip road as a function of the radius of curvature.

n e x e s

A N E XE S

0

10

20

30

40

50

60

70

40 50 60 70 80 90 100 110 120

Rayon de la courbe (m)

V (k

m/h

)

Radius of the curve (m)

58

59

ICTAAL is the technical reference document for the designing of motorways in inter-urban areas,which are divided carriageway roads with at least two lanes in the link sections, with gap-gradedjunctions, isolated from their surroundings.

The document indicates the general principles to be taken into account when preparing newinfrastructure projects or improving the existing network and provides the basic technical rules relatedto definition of geometric elements of the planned infrastructure.

For the national road network, Circular No. 2000 – 87 dated 12 December 2000 gives this documentthe status of National Instruction on Technical Design Requirements for Rural Motorways.

For the other road networks, Regional Authorities may use this Technical Instruction to prepareprojects under their responsibility.

Document available under the reference B0103 from the SETRA Sales Office

46, avenue Aristide Briand - BP 100 - 92225 Bagneux Cedex - France

Phone: 33 1 46 11 31 53 - Fax: 33 1 46 11 33 55

Website: http://www.setra.equipement.gouv.fr

Sales price: FRF120 (€18,29)