Final Report (Transportation Planning & Design)

Project Team 2 (Super-Street Configuration) Roadway Design Project

Tyler Martin, Kamania Ray, Josia Tannos, Yihan Wu, and Arman Yosal

CEE-4600 Transportation Planning and Design

July 7, 2015

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Project Team 2 (Super-Street Configuration)

____________________________________________________________________

Georgia Institute of Technology

July 7, 2015

Dr. Luh,

Second Street is currently disjointed from business and operations close to Adams Road due to

a large heavily wooded area, railroad and grade separation. At this time, drivers are forced to

find alternative routes to businesses located along First Street leading to increased travel times

and congestion outside of the travel generator’s area. Connecting First and Second Street has

been an issue as traversing through the wooded area from above would be difficult and would

incur enormous costs to the city. It is recommended that a connecting street be created, along

with a bridge over the existing railroad. The following report provides final recommendations for

a new street called Main Street. Included in the report are calculations, drawings, tables, and

figures that clearly illustrate the reasoning behind our recommendations.

Sincerely,

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Tyler Martin,

Kamania Ray,

Josia Tannos,

Yihan Wu,

Arman Yosal

Table of Contents

I. Cover Page……………………………………………………………………………......1 II. Letter of Transmittal…………………………………………………………………....... 2 III. Table of Contents…………………………………………………………………………3 IV. List of Figures…………………………………………………………………………......5 V. List of Tables…………………………………………………………………………...... 6 VI. List of Appendices……………………………………………………………………...... 7 VII. List of Exhibits………………………………………………………………………...... 8 VIII. Executive Summary…………………………………………………………………...... 9 IX. Introduction……………………………………………………………………………...... 11 X. Procedure……………………………………………………………………………...... 12

A. Super-Street Configuration Traffic Volumes……………………………...... 12 B. Signal Warrant Analysis……………………………………………………...... 13

1. Criteria 2. Main Street and Adams Road Intersection (Signalized) 3. East U-turn Intersection (Signalized) 4. West U-turn Intersection (Signalized) 5. Main Street and Driveways Intersection (Unsignalized)

C. Capacity Analysis for Unsignalized Intersection…………………………...... 15 1. Introduction 2. Main Street and Driveways Intersection

D. Capacity Analysis for Signalized Intersection………………………….......... 16 1. Introduction 2. Main Street and Adams Road Intersection 3. West U-turn Intersection 4. East U-turn Intersection

E. Turn Bay Length Calculations…………………………..................................17 F. Horizontal Curve Calculations…………………………..................................18

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1. Horizontal Curve 1 2. Why is only one horizontal curve needed? 3. Why did we choose not to do lane drops and adds in the horizontal

curve? G. Vertical Curve Calculations…………………………......................................22

1. Vertical Curve 1 2. Vertical Curve 2 3. Vertical Curve 3 4. Vertical Curve 4 5. Vertical Curve 5 6. Why did we decide to go over the railroad? 7. How did we choose to handle the extra fill costs?

XI. Proposed Roadway Facility…………………………................................................36 A. Drawings B. Median Placement and Sizing C. Protected Turn Placement D. U-Turn Placement E. Driveway Placement F. Lane Drops/Adds/Shifts G. Turning Radius Considerations

XII.Final Cost Calculations………………………….......................................................38 A. Cost Table

XIII. Conclusion…………………………..........................................................................39 XIV. QA/QC Log………………………….......................................................................39 XV. Appendices (includes all figures and tables) …………………………..................40-78 XVI. Exhibits………………………….............................................................................79-91

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List of Figures Figure 1.1 – Initial Traffic Assignment. ……………………………………………………………… 40 Figure 1.2 – Final Traffic Assignment. ……………………………………………………………….40 Figure 2.1 – Warrant 3 Analysis for Main St. and Adams Rd. (AM). ……………………………..41 Figure 2.2 – Warrant 3 Analysis for Main St. and Adams Rd. (PM). ……………………………. 42 Figure 2.3 – Warrant 3 Analysis for West U-turn (AM). …………………………………………….43 Figure 2.4 – Warrant 3 Analysis for West U-turn (PM). …………………………………………….44 Figure 2.5 – Warrant 3 Analysis for East U-turn (AM). …………………………………………… 45 Figure 2.6 – Warrant 3 Analysis for East U-turn (PM). …………………………………………… 46 Figure 2.7 – Warrant 3 Analysis for Driveways Intersection (AM). ………………………………. 47 Figure 2.8 – Warrant 3 Analysis for Driveways Intersection (PM). ………………………………. 48 Figure 3.1 – TWSC Analysis of Main Street and Driveway Intersection #4 (AM).……………….49 Figure 3.2 – TWSC Analysis of Main Street and Driveway Intersection #4 (PM).……………….50 Figure 4.1 – HCS Analysis of Main Street and Adams Road Intersection #1 (AM). …………....51 Figure 4.2 – HCS Analysis of Main Street and Adams Road Intersection #1 (PM)…………… ..52 Figure 4.3 – HCS Analysis of West U-turn Intersection #2 (AM). ……………….………………..53 Figure 4.4 – HCS Analysis of West U-turn Intersection #2 (PM). …………………………………54 Figure 4.5 – HCS Analysis of East U-turn Intersection #3 (AM). ………………………………… 55 Figure 4.6 – HCS Analysis of East U-turn Intersection #3 (PM). ………………………………....56 Figure 5.1 – Intersection Number Assignment. ……………………………………………………..59 Figure 6.1 – Horizontal Curve Design ………………………………………………………………62 Figure 6.2 – Elevation Rise.……………………………………………………………………………65 Figure 6.3 – Super-elevation Transition on Tangent Line. …………………………………………65 Figure 6.4 – Horizontal Curve Connecting Two Tangent Lines. …………………………………..66 Figure 6.5 – Super-elevation Transition.……………………………………………………………..66 Figure 6.6 – Middle Ordinate and Radius of Horizontal Curve…………………………………….67 Figure 7.1 – Curve Number Assignment …………………………………………………………….68 Figure 7.2 – Tangent Lines of Curve 1.………………………………………………………………69 Figure 7.3 – Tangent Lines of Curve 2.………………………………………………………………70 Figure 7.4 – Calculation of Intersection Coordinate.………………………………………………..72 Figure 7.5 – Tangent Lines of Curve 3.………………………………………………………………73 Figure 7.6 – Calculation of Elevation of PVC in Curve 3.…………………………………………..74 Figure 7.7 – Tangent Lines of Curve 4.………………………………………………………………75 Figure 7.8 – Intersecting Curves.……………………………………………………………………...76 Figure 7.9 – Tangent Lines of Curve 5.………………………………………………………………77

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List of Tables Table 2.1 – Main St. and Adams Rd. Traffic Volume (AM). ………………………………………..41 Table 2.2 – Main St. and Adams Rd. Traffic Volume (PM). ………………………………………..42 Table 2.3 – West U-turn Traffic Volume (AM).……………………………………………………….43 Table 2.4 – West U-turn Traffic Volume (PM).……………………………………………………….44 Table 2.5 – East U-turn Traffic Volume (AM). ………………………………………………………45 Table 2.6 – East U-turn Traffic Volume (PM). ………………………………………………………46 Table 2.7 – Driveways Intersection Traffic Volume (AM). ………………………………………….47 Table 2.8 – Driveways Intersection Traffic Volume (PM). ………………………………………….48 Table 4.1 – Phasing Sequence Main Street and Adams Road Peak Hour (AM). ……………….57 Table 4.2 – Phasing Sequence Main Street and Adams Road Peak Hour (PM). ……………….57 Table 4.3 – Phasing Sequence East U-turn Peak Hour (AM).……………………………………..57 Table 4.4 – Phasing Sequence East U-turn Peak Hour (PM).……………………………………..57 Table 4.5 – Phasing Sequence West U-turn Peak Hour (AM). ……………………………………58 Table 4.6 – Phasing Sequence West U-turn Peak Hour (PM).…………………………………….58 Table 5.1 – Turn Bay Lengths at Intersection 1 (Main Street & Adams Road). ………………….60 Table 5.2 – Turn Bay Lengths at Intersection 2 (West U-turn). ……………………………………60 Table 5.3 – Turn Bay Lengths at Intersection 3 (East U-turn). …………………………………….60 Table 5.4 – Turn Bay Lengths at Intersection 4 (Main Street & Driveways).……………………..61 Table 6.1 – Minimum Radius Using Limiting Values of e and f…………………………………….63 Table 6.2 – Minimum Sight Distance Requirement…………...…………………………………. ...64 Table 7.1 – Design Controls for Stopping Sight Distance and Rate of Vertical Curvature for

Crest Vertical Curve…………...…………………………………. ...........................….69 Table 7.2 – Elevation at Every Half Station (Curve 1)……...………………………………….……70 Table 7.3 – Design Controls for Stopping Sight Distance and Rate of Vertical Curvature for Sag

Vertical Curve…………...…………………………………. ... …………………………71 Table 7.4 – Elevation at Every Half Station (Curve 2)..……...…………………………………. ….73 Table 7.5 – Elevation at Every Half Station (Curve 3)…..…...…………………………………. ….75 Table 7.6 – Elevation at Every Half Station (Curve 4)…..…...…………………………………. ….76 Table 7.7 – Elevation at Every Half Station (Curve 5)…..…...…………………………………. ….78

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List of Appendices Appendix 1 – Traffic Volume Assignment. ………………………………………..…………………40 Appendix 2 – Signal Warrant Analysis. ………………………………………..…………………….41 Appendix 3 – Capacity Analysis for Unsignalized Intersections………………………..……. …..49 Appendix 4 – Capacity Analysis for Signalized Intersections …….…………………………… …51 Appendix 5 – Turn Bay Length Calculations ………………………………………………………..59 Appendix 6 – Horizontal Curve Calculations ………………………………………………………..62 Appendix 7 – Vertical Curve Calculations ………………………………………………………..68

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List of Exhibits (at end of folder) Exhibit 1 – Section 1 Exhibit 2 – Section 2 Exhibit 3 – Section 3 Exhibit 4 – Section 4 Exhibit 5 – Section 5 Exhibit 6 – Section 6 Exhibit 7 – Section 7 Exhibit 8 – Intersection Detail 1 Exhibit 9 – Intersection Detail 2 Exhibit 10 – Intersection Detail 3 Exhibit 11 – Intersection Detail 4 Exhibit 12 – Overall Layout Exhibit 13 – Cross-section View

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Executive Summary This report summarizes the conceptual design details of a proposed road segment which

connects the First Street and the Second Street in Fulton County.

Existing Conditions 1. Truck percentage along the Main Street and Adams Road: 10%

2. Peak Hour Factor (PHF) = 0.9

3. The intersection of First Street and Adams Road has poor levels of service, which is

operating at LOS F during peak periods.

4. There are no bicycle or transit facilities along the corridor.

5. A railroad is located between First Street and Second Street

6. The current configuration of the intersection of First Street and Adams Road renders

drivers vulnerable to car crashes.

Objective of Design Report This design report focuses on road improvements including the installation of new traffic signals,

signal system signal system optimization, turn pockets or lanes, and storage lanes and/or

extended turn lanes. The proposal is based on the project purpose and need, existing/future

conditions at each location, as well as suggested improvements. Level of service, delay, signal

warrants, safety, property impacts and cost were all considered during the development and

evaluation of the proposal.

The goal of this report is to provide an alternate intersection configuration to accommodate

increasing traffic volume, identify pertinent issues and constraints, and estimate the cost of the

potential improvements.

Projected Conditions After Improvements

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1. Design Speed of Main Street and Adam Road is 45 mph and 35 mph, respectively.

2. The intersection of Main Street and Adams Road is redesigned using the super-street

configuration, with appropriate intersection sight distances.

3. Road cross section: including gutter and curb (2.5 feet), utility strip (5 feet), sidewalk ( 5

feet) and sidewalk extension to right-of-way (5 feet).

4. At least Level of Service D for each movement at the intersection of Main Street and

Adams Road.

5. A bridge that effectively crosses the railroad.

6. Two driveways on the main street.

7. Designated turn bays which give priorities to the turning movements.

8. Pedestrian crosswalks at the intersection.

Next Steps and Implementation Following the approval of the report by the County, further recommendations need to be offered

to assist right-of-way acquisition, utility work, design, and construction.

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Introduction The goal of this project was to provide engineering services to a county located in an urban

area. The team was tasked with developing a scheme for providing a connection between First

Street and Second Street that would accommodate and redirect design year traffic through the

modification of intersection configurations. First Street and Second Street are primarily 2-lane

roadways but are currently separated by private properties and a railroad. Due to limited budget,

the design proposal aims to create a design, which is sensitive to monetary constraints without

compromising the Level of Service.

This report includes the following primary improvements:

1. A new road connecting First Street and Second Street

2. An intersection layout conversion of Main Street and Adams Road from a regular

intersection to a Super-Street Configuration

3. A bridge that effectively crosses the railroad

4. A proposal for two driveways on Main Street

The main purpose of report this report is to provide background information and calculations for

the conceptual scheme design drawings produced under the direction of the design guidelines.

A cost balance sheet was also produced and included in the report for the use of Right-of-Way

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acquisition and estimation of construction costs. All detailed calculations, tables, and figures are

included in the appendices.

This report is structured into three primary sections:

A. Section 1 encapsulates the guiding principles and calculations used in producing

the concept design (i.e. Signal warrant analysis, horizontal and vertical curve

alignments, etc.)

B. Section 2 contains information about the newly proposed concept design (i.e.

drawings, reasoning and choices, etc.)

C. Section 3 provides final cost calculations, conclusions, a QA/QC log, and an

appendices (including exhibits, tables and design drawings)

Procedure The following section outlines the calculations that were completed in order to form a roadway

design proposal. These calculations include traffic assignment, HCS analysis, signal warrant

analysis, turn bay length, horizontal curve calculations, vertical curve calculations, and

super-elevation calculations.

A. Super-Street Configuration Traffic Volumes The superstreet configuration requires that through and left turning vehicles from the minor

street approach turn right, proceed to the downstream U-turn and then return in the opposite

direction. The movements from the major street are unaffected as the main intersection still

allows for all movements from the major street. A major benefit of this configuration is that

signalization is simplified into two phases while a typical intersection could have as many as

eight. The two signal phases first give a green light to the major street through traffic, followed

by the second phase which gives the green light to the left turns from the major street at the

same time as the right turns from the minor street. The two median U-turn locations would also

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be signalized and would operate similarly with only two phases; the first again being the through

traffic and the second allowing the U-turn movement. The reduction in the number of

movements that occur at each intersection allows the intersection to operate more efficiently

and to give more of the green time to the heavy through movements. The other major benefit

the number of opportunities for cars to collide are minimized. Another benefit is the improved

ability to coordinate the signals along the corridor, which reduces overall travel time.

The first intersection is converted to a super street intersection and traffic volume is then

recalculated based on existing data. Additionally, the two driveways are combined, with each

locating on one side of the main street. The Figure 1.2 shows the result of traffic assignment.

B. Signal Warrant Analysis

B.1 Criteria (MUTCD)

Support:

The Peak Hour signal warrant is intended for use at a location where traffic conditions are such

that for a minimum of 1 hour of an average day, the minor-street traffic suffers undue delay

when entering or crossing the major street.

Standard:

This signal warrant shall be applied only in unusual cases, such as office complexes,

manufacturing plants, industrial complexes, or high-occupancy vehicle facilities that attract or

discharge large numbers of vehicles over a short time.

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The need for a traffic control signal shall be considered if an engineering study finds that the

criteria in either of the following two categories are met:

A. If all three of the following conditions exist for the same 1 hour (any four consecutive

15-minute periods) of an average day:

1. The total stopped time delay experienced by the traffic on one minor-street

approach (one direction only) controlled by a STOP sign equals or exceeds: 4

vehicle-hours for a one-lane approach; or 5 vehicle-hours for a two-lane

approach, and

2. The volume on the same minor-street approach (one direction only) equals or

exceeds 100 vehicles per hour for one moving lane of traffic or 150 vehicles per

hour for two moving lanes, and

3. The total entering volume serviced during the hour equals or exceeds 650

vehicles per hour for intersections with three approaches or 800 vehicles per

hour for intersections with four or more approaches.

B. The plotted point representing the vehicles per hour on the major street (total of both

approaches) and the corresponding vehicles per hour on the higher-volume

minor-street approach (one direction only) for 1 hour (any four consecutive 15-minute

periods) of an average day falls above the applicable curve in Figure 4C-3 for the existing

combination of approach lanes.

Option:

If the posted or statutory speed limit or the 85th-percentile speed on the major street exceeds

70 km/h or exceeds 40 mph, or if the intersection lies within the built-up area of an isolated

community having a population of less than 10,000, Figure 4C-4 may be used in place of Figure

4C-3 to satisfy the criteria in the second category of the Standard.

This design project uses Warrant 3 (peak hour warrant) from MUTCD to determine if an

intersection can be controlled by a traffic signal since only peak hour counts are available for

each intersection. Higher speed curve in peak hour warrant will be used since Main St. has a

design speed of 45 mph. There are a total of four intersections that are analyzed using the peak

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hour warrant, which are Main Street and Adams Road intersection, East U-turn, West U-turn,

and Main Street and driveways intersection. There are two sets of analysis in each intersection

to include the morning and evening peak hour.

B.2 Main Street and Adams Road Intersection The Main Street and Adams Road intersection has three lanes in each direction in the major

street and one continuous right turn in the minor street. This continuous right turn will not be

included in the analysis because it is not controlled by the traffic signal. In this case, left turn

from major street will be considered as the minor street volume and it will not be included in the

major street volume calculation. Traffic volume of this intersection can be seen in the Table 2.1

and 2.2. In this intersection, 2 or more lanes & 1 lane curve is used to do the warrant analysis.

According to the Figure 2.1 and 2.2, traffic signal can be considered in this intersection.

B.3 West U-turn Intersection The West U-turn has 2 through lanes in the eastbound direction and one U-turn lane. The

westbound direction through lane will not be considered in this analysis because it does not in

conflict with other lanes. The two through eastbound lanes are considered as major street and

the U-turn is considered as minor street. Traffic volume of this intersection can be seen in the

Table 2.3 and 2.4. The 2 or more lanes & 1 lane curve is used to do the warrant analysis.

According to Figure 2.3 and 2.4 below, traffic signal can be considered in this U-turn.

B.4 East U-turn Intersection The East U-turn has 2 through lanes in the westbound direction and one U-turn lane. The

eastbound direction through lane will not be considered in this analysis because it does not in

conflict with other lanes. The two through westbound lanes are considered as major street and

the U-turn is considered as minor street. Traffic volume of this intersection can be seen in the

Table 2.5 and 2.6. The 2 or more lanes & 1 lane curve is used to do the warrant analysis.

According to Figure 2.5 and 2.6, traffic signal can be considered in this U-turn intersection.

B.5 Main Street and Driveways Intersection

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The Main Street and driveways intersection has two lanes in each direction in the major street

and one lane in each direction in the minor street. Traffic volume of this intersection can be seen

in the Table 2.7 and 2.8. The 2 or more lanes & 1 lane curve is used to do the warrant analysis.

According to Figure 2.7 and 2.8, traffic signal is not necessary in this intersection.

C. Capacity Analysis for Unsignalized Intersection

C.1 Introduction Unsignalized intersections are used to regulate low volume of traffic flow between the major and

minor street. Based on the peak hour warrant analysis, only one intersection that does not need

traffic signal, which is the Main Street and driveways intersection. There are two ways to handle

unsignalized intersections, which are two-way stop-controlled (TWSC) and all-way

stop-controlled (AWSC). Stop sign control requires that drive come to a complete stop before

entering the intersection. The AWSC requires drivers on all intersections approaches to stop,

while TWSC requires only the drivers on the stop-controlled approaches to stop. This design

report uses two-way stop-controlled to handle the Main Street and driveways intersection.

The capacity analysis assumes one lane can hold 1,400 vehicles per hour. This intersection is

analyzed in two sets because it has different peak hour volume for morning and evening rush

hour. Highway Capacity Software (HCS) TWSC is used to analyze this intersection and give the

level-of-service (LOS) of the intersection. There is no minimum requirement of LOS for

unsignalized intersection, therefore there is no consideration made to add extra lanes regarding

the LOS.

C.2 Main Street and Driveways Intersection In the AM peak hour, the TWSC configuration creates a level of service of B in the major street

for both left turn lane and shared through and right turn lane and a level of service of F in the

minor street for shared left and right turn. (Figure 3.1) In the PM peak hour, the TWSC

configuration also creates a level of service of B in the major street for both left turn lane and

shared through and right turn lane and a level of service of F in the minor street for shared left

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and right turn. (Figure 3.2) There is no further refinement regarding the LOS grade in the minor

street.

D. Capacity Analysis for Signalized Intersection

D.1 Introduction

Signalized intersections are used to regulate high traffic volume to give an adequate

level-of-service. Traffic signals provide control by showing green indications only to those

movements that can travel through the intersection together at the same time. A time

separation, indicated by the yellow time and red clearance, is provided between each set of

these compatible movements. Based on the peak hour warrant, there are three intersections

that can be considered to use a traffic signal and they are Main Street and Adams Road

intersection, East U-turn, and West U-turn. Highway Capacity Software (HCS) is used to

analyze the intersection and get the minimum number of lanes required to satisfy minimum

level-of-service on each intersection. This capacity analysis assumes a peak hour of 0.90, ten

percent of the vehicle volumes are heavy vehicle, a design vehicle of WB-40, and a saturation

of 1,400 vehicles per hour per lane. The minimum LOS criteria for this capacity analysis are D

for each movement. Three intersections are analyzed using the peak hour volume in the

morning and in the evening.

D.2 Main Street and Adams Road Intersection

The Main Street and Adams Road intersection has a super-street configuration; the westbound

and eastbound direction has one through lane, one right turn bay, and left turn bay while the

northbound and southbound direction has a continuous right turn lane. In the HCS analysis,

continuous right turn in the minor street is not included because it is not controlled by the traffic

signal. There are two analyses for morning peak hour and evening peak hour. These two

analyses use different phasing sequence and green time (Table 4.1 and Table 4.2). In this case,

two phasing sequence may be considered in order to manage the intersection. As seen in

Figure 4.1 and 4.2, these analyses satisfy the minimum LOS requirement of D.

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D.3 West U-turn Intersection

The West U-turn is needed for super-street configuration to accommodate through and left turn

in southbound direction. In this intersection, there is no northbound and southbound direction.

The eastbound direction has two through lanes while the westbound direction has one through

lane and one U-turn lane. There are two analyses for morning peak hour and evening peak

hour. These two analyses use different phasing sequence and green time (Table 4.3 and Table

4.4). In this case, two phasing sequence may be considered in order to manage the

intersection. As seen in Figure 4.3 and 4.4, these analyses satisfy the minimum LOS

requirement of D.

D.4 East U-turn Intersection

The East U-turn is needed for super-street configuration to accommodate through and left turn

in northbound direction. In this intersection, there is no northbound and southbound direction.

The eastbound direction has one through lane and one U-turn lane while the westbound

direction has two through lane. There are two analyses for morning peak hour and evening peak

hour. These two analyses use different phasing sequence and green time (Table 4.5 and Table

4.6). In this case, two phasing sequence may be considered in order to manage the

intersection. As seen in Figure 4.5 and 4.6, these analyses satisfy the minimum LOS

requirement of D.

E. Turn Bay Length Calculations The addition of turning lanes increases capacity for the approach by removing turning

movements from the through traffic stream, and it also allows for the use of a shorter cycle

length or allocation of green time to other critical movements.

In this project, both the left turn lanse and right turn lanse are provided at the intersection of

Adams Road and Main Street. Also, the left-turn lanes will be added to the U-turn intersection in

order to protect the U-turn vehicles. The tables in Appendix 5 show the determination of left-turn

and right-turn bay lengths. The turn bay lengths at intersection 1 (Table 5.1) , 2 (Table 5.2) and

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3 (Table 5.3) are calculated based on the back of queue generated by signalized HCS analysis,

while the calculation at intersection 4 (Table 5.4) is produced based on the result of

unsignalized HCS analysis (Appendix 3).

It is worth mentioning that intersection 4 is an unsignalized intersection and HCS does not

produce the 95% queue length for the Eastbound and Westbound through traffic. And since the

95% queue lengths for the eastbound and westbound traffic are quite short during either AM or

PM peak hours, the project team applied 50+L ( Q=50’, L=185’, Turn Bay Length = 235’) as

the left turn bay length for both west and east approaches of the intersection. For the detailed

analysis tables and Figures, please see Appendix 5.

F. Horizontal Curve F1 Horizontal Curve Calculations

Horizontal curve is an arc of a circle used to provide a transition between two tangent lines with

angle of greater than 0ᵒ. Horizontal curve, however, is not required if the angle between the

tangent lines is less than 1ᵒ for design speed of greater than or equal to 45 mph, or less than 2ᵒ

for design speed of less than or equal to 40 mph.

We set the angle between tangent lines of First Street and roadway to be 30.99ᵒ, as shown in

Figure 6.1.

Since the angle is greater than 1ᵒ, a horizontal curve between First Street and roadway is

required.

For horizontal curve 1:

Design Speed

Design speed = 45 mph.

Super Elevation Rate e = 4%.

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Radius

As shown in Table 6.1, R = 711 ft.

Degrees of Curvature .D = R

5729.6

D = 8.059ᵒ.

T

,anT = R * t I2

.ngle bewteen tangent linesI = a

T = 197.11 ft.

Slope Ratio Slope ratio = 1:150.

Minimum Sight Distance

From Table 6.2, the minimum sight distance is 360 ft.

Super Elevation

The super elevation rate (e) is 4%. We choose e to be 4% by considering the space that we

have from the PC station of horizontal curve 1 to the stop bar of the Westbound on First Street.

The space that we have is 334 feet. We have to make sure that 80% of the super elevation

transition is not more than the available space between the PC station and the stop bar.

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In order to determine the super elevation transition, first we need to determine the elevation rise

at pavement edge, X.

X = e * L levation rise at pavement edgeL = e

.04e = 0

As shown in Figure 6.2, the roadway has four lanes with an 18-feet-median. Hence,

.6L = 12′ + 12′ + 18′ + 12′ + 12′ = 6 ′

.04 .64X = 0 * 66′ = 2 ′

Now, we need to determine the super elevation transition.

T Slope ratio)S = ( * X

At design speed of 45 mph, we know that the slope ratio is 1:150.

T 50 96S = 1 * 2.64′ = 3 ′

As the conclusion, the super elevation transition length is 396 ft. The transition must have

appropriate placement between the horizontal curve and tangent lines. That is, 80% of the

super elevation transition must be located on tangent lines and 20% of the super elevation

transition must be placed on the curve.

TS = 396′ 0% T8 * S = 316.8′ 0% T 9.22 * S = 7 ′

Based on the calculation, there must be at least 316.8 ft space available from the PC station of

the curve to the stop bar of the Westbound on First Street, as shown in Figure 6.3.

Figure 6.5 shows the final design of horizontal curve.

Curve Length

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The curve length of horizontal curve must be determined for the stationing of the roads,

because the distance to go from a point that lies at one tangent line to the other point at the

other tangent line before and after horizontal curve is constructed will not be the same, as

shown in Figure 6.4.

The length of horizontal curve 1 is calculated as:

C 00L = 1 * ID

ngle bewteen tangent linesI = a egrees of curvatureD = d

We know that the degrees of curvature of horizontal curve 1 is 8.059ᵒ. We set the angle

between tangent lines of horizontal curve 1 to be 30.99ᵒ so that we do not need to add more

cost by constructing another horizontal curve between roadway and Second Street.

C 00 84.54L = 1 * 8.059ᵒ30.99ᵒ = 3 ′

As the conclusion, the length of horizontal curve 1 is 384.54 ft.

Critical Sight Distance In constructing a horizontal curve, a minimum sight distance requirement must be satisfied for

safety of the drivers.

The sight distance is determined by middle ordinate and critical lane radius.

As shown in Figure 6.6, we know that the critical lane radius of horizontal curve 1 is 684 ft and

the angle between tangent lines is 30.99ᵒ.

1 os ) M = r * ( − c I2

ritical lane radius r = c I=30.99ᵒ

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Therefore,

84 r = 6 ′

1 os ) M = 684′* ( − c 2

30.99ᵒ 4.86 M = 2 ′

In order to calculate the minimum sight distance,

1 os )M = r * ( − c r28.65 S*

ritical lane sight distance S = c

By rearranging the equation,

rccos(1 )S = r28.65 * a − r

M rccos(1 ) S = 684′

28.65 * a − 684′24.86′

69.93 S = 3 ′

As the conclusion, the critical sight distance is 369.93 ft. Therefore, horizontal curve 1 meets the

minimum sight distance requirement because the minimum sight distance is 360 ft.

F2 Why is only one horizontal curve needed?

In this project, we set the angle between tangent lines of horizontal curve 1 to be 30.99ᵒ. We

only need one horizontal curve because the angle between the tangent line of the roadway

(Main Street) and the second street is less than 1ᵒ at design speed of 45 mph.

F3 Why did we choose not to do lane drops and adds in the horizontal curve?

We choose not to do lane drops and adds in the horizontal curve to simplify the calculation of

the super elevation transition. Super elevation transition is calculated based on the distance of

the right-of-way of the road and elevation grade, and if the width of the road is changing, the

super elevation transition calculation will be more complex. Moreover, it will be dangerous for

drivers to change lane on an inclined roads.

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G. Vertical Curve Vertical curve is used to provide a transition between two roadways with an angle between

them. The need to use a vertical curve is determined by the design speed and absolute

difference between the grades of the two roadways. For design speed of 45 mph, vertical curve

is required if the maximum differences of the elevation grades exceeds 0.7%.

In constructing vertical curves, we have to make sure that the end of one vertical curve (PVT

station) does not overlap with the beginning of the other vertical curve (PVC station) and vice

versa.

The following formulas are used in the calculation of vertical curves.

G1 2|A = | −G CL = A * K

1 pvcY = 2* LC100

G2−G1 * x2 +G * x * Y

1 levation grade of the first roadwayG = E 2 levation grade of the second roadwayG = E

orizontal distance in 100 ftx = H C urve lengthL = C ate of curvatureK = R

pvc levation at PV C station of the curveY = E

For crest curve with S≤L:

L = |A| S*2

200 ( + )* √3.5 √22

00S = L * 2 * |A|( + )√3.5 √2

2

For crest curve with S>L:

00L = 2 * S − 2 * |A|( + )√3.5 √2

2

L 00 }S = 21 * { + 2 * |A|

( + )√3.5 √22

For sag curve with S≤L:

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A|L = | * S2

200 * 12+S tan (1ᵒ) *

For sag curve with S>L:

00L = 2 * S − 2 * |A|2+S tan (1ᵒ) *

urve length L = C ight distance S = S

The final design of the vertical curves is shown in Figure 7.1.

G1. Vertical Curve 1 Vertical curve 1 is a crest curve that connects First Street and the roadway.

Refer to Figure 7.2.

4 − .435)| .435A = | − ( 0 = 4

Since A is greater than 0.7, a vertical curve is required.

The design speed is 45 mph.

From Table 7.1, at a design speed of 45 mph, a crest vertical curve has a rate of vertical

curvature of 61 and minimum stopping sight distance of 360 ft.

Curve Length The curve length of vertical curve 1 is calculated as:

C L = A *K bsolute grade difference A = A ate of vertical curvatureK = R

We know that A is 4.435 and K is 61.

C .435 1 70.52L = 4 * 6 = 2 ′

As the conclusion, the curve length of vertical curve 1 is 270.52 ft.

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Elevation Equation For the first vertical curve:

1 + %G = 4 2 − .435%G = 0

Ypvc is the elevation at PVC station. We know that the elevation at PVI station is 1020 and the

grade of the first street going from West to East is +4%. The middle of the curve, PVI station, is

located midway between PVC and PVT station.

The elevation at PVC station can be calculated as:

pvc 020 1 014.59Y = 1 − 2LC *G = 1

As the conclusion,

014.59Y = −4.4352* 100

270.52 * x2 + 4 * x + 1

− .819 014.59Y = 0 * x2 + 4 * x + 1 The elevation in curve 1 is provided in Table 7.2.

Critical Sight Distance Assume: S≤L

L = |A| S*2

200 ( + )* √3.5 √22

00S2 = L * 2 * |A|( + )√3.5 √2

2

S=362.83’

The calculated sight distance is 362.83 ft. However, S is greater than L, which means that our

assumption is incorrect.

For S>L:

00L = 2 * S − 2 * |A|( + )√3.5 √2

2

L 00 }S = 21 * { + 2 * |A|

( + )√3.5 √22

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.435 A = 4 urve length L = C ight distance S = S

We know that the curve length of vertical curve 1 is 270.52 ft.

Therefore,

78.59S = 3 ′

S is greater than L, which means that the equation that we use is correct.

As a result, the critical sight distance is 382.79 ft, and it is more than the minimum sight distance

which is 360 ft.

G2. Vertical Curve 2 In constructing the second vertical curve, we must find the maximum grade of increase from the

roadway to 33 ft above the railroad that is able to meet the requirements of vertical curve (sight

distance, locations of PVC and PVT stations of all curves).

Vertical curve 2 is a sag curve that connects First Street and the roadway.


(− .435) .430| .865A = | 0 − 6 = 6



From Table 7.3, at a design speed of 45 mph, a sag vertical curve has a rate of vertical

curvature of 79 and minimum stopping sight distance of 360 ft.

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C .865 9 42.34L = 6 * 7 = 5 ′



1 + .430%G = 6 2 − .435%G = 0

Ypvc is obtained by determining the location of PVI station, which is located midway between

PVC and PVT station.

As shown in Figure 7.4, line 2 has a slope of 0.0643. Both point A and B in the figure lie at the

same line as line 2, so the slope is also 0.0643. The x-coordinate of point B is calculated by

subtracting the PVI station of vertical curve 3 with half of the length of curve 3. The calculation

of vertical curve 3 will be shown in the next part.

6.43% is the maximum grade that we can obtain up to 3 significant figures without any curves

intersecting from one to another (between vertical curve 2’s PVT station to vertical curve 3’s

PVC station). We tried to find the best possible elevation grade that will not produce any

intersection between curves.

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lopeS = x2−x1y2−y1

.06430 = 2450−[6.43 ]−xint* 261

1042.35−[−0.00435 xint+1020]*

int 785.59x = 1

By using line 1,

− .00435 785.59 020Y = 0 * 1 + 1

pvc 012.23Y = 1

As the conclusion,

.633 .00435 012.23Y = 0 * x2 − 0 * x + 1

The elevations at curve 2 is provided in Table 7.4.

Critical Sight Distance

Assume: S≤L

A|L = | * S2

200 * 12+S tan (1ᵒ) *


We know that the curve length of vertical curve 2 is 542.34ft.

Therefore,

62.87S = 3 ′

S is less than L, which means that the equation that we use is correct.

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which is 360 ft.

G3. Vertical Curve 3

Vertical curve 3 is a crest curve.


6.430 | .430A = | − 0 = 6




curvature of and minimum stopping sight distance of 360 ft.




C .430 1 92.23L = 6 * 6 = 3 ′

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Elevation Equation

For the first vertical curve:

1 + .430%G = 6 2 − %G = 0

From the previous part (calculation of vertical curve 2), we can determine the equation of line 2.

.0643 042.35Y = 0 * x + 1 starts from PV I of curve 3x

The x coordinate of the PVC station of vertical curve 3 is located halfway from PVI station.

pvc .0643 − 042.35 029.74Y = 0 * 2392.23 + 1 = 1

As the conclusion,

− .819 .43 029.74Y = 0 * x2 + 6 * x + 1

The elevation in curve 3 is provided in Table 7.5.


Assume: S≤L

L = |A| S*2

200 ( + )* √3.5 √22


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Therefore,

62.87S = 3 ′

S is less than L, which means that the equation that we use is correct.


which is 360 ft.


Vertical curve 4 is a crest curve.


0 − .70)| .70A = | − ( 3 = 3




curvature of 61 ft and minimum stopping sight distance of 360 ft.

In vertical curve 4, we choose the decreasing elevation grade to be 3.70 % because if we use

higher grade, the curve will intersects with another curve.

As shown in Figure 7.8, if we use 7%, then there will be six vertical curves required, and two

curves will be intersecting.

We tried to find the best possible elevation grade without any intersection between curves.

Curve Length

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The curve length of vertical curve 4 is calculated as:

CL = A * K bsolute grade difference A = A ate of vertical curvatureK = R


C .70 1 25.70L = 3 * 6 = 2 ′



1 + %%G = 0 2 − .70 %G = 3

pvc 042.35Y = 1

As the conclusion,

− .819 042.35Y = 0 * x2 + 1

The elevations in curve 4 is provided in Table 7.6.


Assume: S≤L

L = |A| S* 2

200 ( + )* √3.5 √22

.70 A = 3 urve length L = C

Page | 34

ight distance S = S


Therefore,

63.05 S = 3 ′

But, S is greater than L. So, we used the incorrect formula.

For S≥L:

00L = 2 * S − 2 * |A|( + )√3.5 √2

2

S=404.51’

Now, S is greater than L, which means that the equation that we use is correct.


which is 360 ft.


Vertical curve 5 is a sag curve.


3.70 − .00)| .70A = | − ( 3 = 6



From Table 7.3, at a design speed of 45 mph, a sag vertical curve has a rate of vertical

curvature of 79 ft and minimum stopping sight distance of 360 ft.

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C .70 9 29.30L = 6 * 7 = 5 ′


Elevation Equation

For the first vertical curve:

1 − .70%G = 3 2 + .00 %G = 3

pvc 029.45Y = 1

As the conclusion,

.633 .70 029.45Y = 0 * x2 − 3 * x + 1

The elevations in curve 5 is provided in Table 7.7.


Assume : S≤L

A|L = | * S2

200 * 12+S tan (1ᵒ) *

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We know that the curve length of vertical curve 5 is 529.62ft.

Therefore,

62.87S = 3 ′

S is less than L, which means that our assumption is correct.


which is 360 ft.

G6 Why did we decide to go over the railroad?

We decided to go over the railroad because if we go under the railroad, based on our

calculation, the vertical curves will intersect with each other. This is because by going at grade

of 7% downwards from First Street to the roadway, by the time it reaches feet below the

railroad, it already moves too far in the horizontal direction, causing the PVT station of curve

before passing the railroad to intersect with PVC station of the curve after the railroad. If the

grade is lower than 7%, the slope of the tangent line will become less steep, causing the

horizontal movement to be even larger, creating smaller space between the PVT station of

curve before the railroad and PVC station of curve after the railroad.

In designing the vertical curve, we make sure that the PVC station of the curve at the West from

the railroad and the PVT station of the curve at the East from the railroad does not lie on the

railroad.

G7 How did we choose to handle the extra fill costs?

In order to minimize the cost, we tried to find the maximum elevation decrease grade from First

Street to the railroad. The maximum decrease grade is 7%. However, if we use 7% as the

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elevation decrease grade, the curve 2’s PVT station and curve 3’s PVC station will intersect By

using optimization method, we get the decrease grade from First Street to the roadway before

passing the railroad to be 6.43%. With 6.43% elevation decrease grade, we try to reach the

existing roadway as soon as possible to reduce the amount of area we need to fill, furthermore

reduce the cost.

On the East side of the railroad, we cannot use decrease elevation grade of 7% because if we

do, then the curves on the East side of the railroad will intersect. If we reduce the grade to get to

the existing roadway as soon as possible to reduce the area needed to be filled, the curve will

still intersect. This is because with lower grade, there will be more horizontal distance change

taken to move at the same elevation. Therefore, at lower grade than 7%, the curves at East

from the railroad will intersect because more horizontal distance is required to reach the same

altitude from the same initial elevation. We decided to go downwards without trying to get to the

existing road as soon as possible because if we do, our curves will intersect. We put the PVT

station of vertical curve 5 at distance of 1000 feet from the railroad. By making sure that the

PVT station of vertical curve 5 is located at 1000 feet from the railroad, the decrease elevation

grade from the railroad to the roadway (located East from the railroad) is 3.70%.

Proposed Roadway Facility The following section gives details about the final roadway facility proposal. The given drawings,

diagrams and reasoning are based on the previously discussed calculations. Please reference

Exhibit 1 through Exhibit 13 for the proposed roadway facility drawings and diagrams.

A. Drawings

Please reference Exhibit 1 through Exhibit 13 for the final layout drawings. These drawings were

completed in AutoCAD and were drawn at a 100 scale. They include all roadway facilities,

pavement markings, queue lengths, stationing, right-of-way limits, radii measurements, and

signal proposals. Please note that 2nd street was not included in the drawing because the new

construction ends at the edge of this street.

B. Median Placement and Sizing

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Median placement and sizing was determined by the required turn bays, u-turns, and driveway

facilities. All medians were minimally sized as to decrease overall costs. In segments where only

one lane is provided, yellow lines were used to prevent emergency vehicle conflicts. Thus, there

are no places along the proposed roadway that contain one lane on either side of a physical

median.

C. Protected Turn Placement The given traffic volumes for the north and south directions (Adams Road) were very high for

the existing roadway because of the reconfiguration to a Super-Street Configuration. When

entered in HCS, scores of E and F were given for many lanes. Therefore, the project team

decided to provide protected right turn lanes for the north and south directions of the Adams

Road and 1st Street intersection. This allows all vehicles exiting from these directions to turn

right without stopping or waiting for a signal. This increased the LOS score and allowed for only

one right turn lane to be used.

D. U-Turn Placement The Super-Street Configuration requires u-turns for all vehicles who are forced to turn right out

of Adams road. According to our Engineering Manager (Dr. John Z. Luh), the distance between

an intersection and a u-turn is usually between 1,000 and 1,500 feet. The project team chose to

use 1,000 feet for the west u-turn. The right u-turn was placed a little further out because of the

horizontal curve. The team felt that the horizontal curve needed to have very simple lanes,

without many adds, drops, or shifts. Having two lanes in each direction provides drivers with a

simple roadway that does not have sight distance issues.

E. Driveway Placement This project required two driveways to be placed somewhere along the roadway. They were

placed a short distance from the east u-turn facility. This allowed the team to keep the amount

of lanes without requiring lane adds or drops down the road. Both of these have left turn lanes.

Per the class discussion, right turn lanes were not included.

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F. Lane Drops, Adds, and Shifts

Lane drops were utilized as soon as possible after intersections in order to decrease the

right-of-way width and cost. This is how the proposed roadway was able to transition back to

two lanes, meeting 2nd Street on the east side and the existing 1st street on the west side.

G. Turning Radius Considerations

For right turns, a radius of 25 was used to design the intersections. For left turns, an inside

radius of 60 was used.

Final Cost Calculations

The following section details the final cost calculations based on the newly designed roadway.

Square footage was taken from the AutoCAD drawing and multiplied by the appropriate

numbers.

Total Costs

Item Cost/SF Square Feet Cost

Paved Area $40/SF 300,871.76 $12,034,870.40

Unpaved Area $20/SF 230,502.39 $4,610,047.80

Grass Area $10/SF 70,776.67 $707,766.70

Bridge $100/SF 3,704.18 $370,418.00

Traffic Signal $80,000/intersection - $240,000

Right-of Way Acquisition $20/SF 353,652.90 $7,073,058.00

Cut/Fill Additional Charge $40/SF 132,192.90 $5,287,716.00

Total - 1,091,700.8 $30,323,876.20

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Table 8.2 Total Project Costs

Conclusion The newly created Main Street successfully creates a connection between the existing First

Street and Second Street without excessive right-of-way acquisition and demolition of existing

roadways. In particular, the HCS analysis gave the project team the most difficulties because of

high traffic volumes. The horizontal and vertical curves were repeatedly adjusted to account for

changes in lane shifts, sight distance requirements, and superelevation requirements. If we had

the chance to re-do this project, we would have figured out the horizontal and vertical curves in

the beginning. One of the primary problems that was experienced in the design process was

adding travel lanes, lane shifts, and lane additions in the horizontal curve. One of main

problems with the design is the fact that the horizontal curve does not account for the lane

changes down the road. The team had to think in reverse in order to come up with horizontal

curve measurements. Overall, the project team is satisfied with the result and did not sacrifice

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adequate government design criteria for decreased costs. The cost is very high, but the layout

of the new roadway successfully accommodates the traffic volume.

QA/QC Log

Content (sections of report) Produced by Checked by

Traffic Volume Assignment Yihan Wu Arman Yosal

Signal Warrant Analysis Arman Yosal Tyler Martin

HCS Analysis (signalized and unsignalized) Arman Yosal Josia Tannos

Turn Bay Length Calculations Yihan Wu Arman Yosal

Horizontal Curve Calculations (including sight

distance)

Josia Tannos Yihan Wu

Vertical Curve Calculations (including sight

distance)

Josia Tannos Yihan Wu

Proposed Roadway Facility Tyler Martin Yihan Wu

Project Costs Tyler Martin Kamania Ray

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Final Report (Transportation Planning & Design)

Documents

Transcript of Final Report (Transportation Planning & Design)