TR9302-SY 930501 TRAFFIC LIGHT
SYNCHRONIZATION PROGRAM !!
"AFTER" STUDY RESULTS
FOR THE
COPPELL SIGNAL SYSTEM
(Contract 582TLF6043)
PREPARED FOR:
THE TEXAS DEPARTMENT OF
TRANSPORTATION
SUBMITTED BY:
THE CITY OF COPPELL, TEXAS
PREPARED BY:
BARTON-ASCHMAN ASSOCIATES, INC.
Dallas, Texas
COPPELL PUBLIC WORKS
DATE: August 25, 1993
TO:. Ken Griffin, City Engineer
VIA. Steven G. Goram, Director of Public~
FROM: Rey Gonzales, Streets Superintenden~/
RE: TLS Grant - After Study Final Documents
Public Works staff has reviewed the attached document and found
it to be in good order. This is based on the concerns outline~ to
Brian Shewski with Barton-Aschman when we met.
If you have any issues you would like to see addressed pleas~ let
me know as soon as possible. It is my intent to forward the /
necessary copies to the State and close this issue out. /!
Please take the time to review the afte ,~D-~~. ~~ached
and provide me with your comments by~eptember ~ ±~J.~
I appreciate your cooperation in this~ter. J
RG/rg
TLSKG. RG
TRAFFIC LIGHT
SYNCHRONIZATION PROGRAM II
"AFTER" STUDY RESULTS
FOR THE
COPPELL SIGNAL SYSTEM
PREPARED FOR:
THE TEXAS DEPARTMENT OF
TRANSPORTATION
SUBMITTED BY:
THE CITY OF COPPELL, TEXAS
PREPARED BY:
BARTON-ASCHMAN ASSOCIATES, INC.
Dallas, Texas
MAY, 1993
EXECUTIVE SUMMARY
The benefits in reduced delay, stops and fuel consumption derived from updating signal timing
plans has been documented throughout the United States. Coordination of signalized
intersections has the potential to provide benefits. The purpose of this report is to summarize
the findings and the actions taken of an arterial signal system improvement project in Coppell,
Texas. This study has been conducted in conjunction with the Texas Department of
Transportation's (TXDOT) Traffic Light Synchronization Program II (TLS II). Funding for this
project came from the Governor's Energy Management Center and were made available to
improve traffic operations.
In this study, the project team of the City of Coppell and Barton-Aschman Associates, Inc.
collected peak hour turning movement counts, field intersection data, signal timing data, and
travel time and delay data. "Before" and "After" studies were conducted to document the
effects on delay, stops and fuel consumption due to the implementation of a "closed-loop"
traffic signal system. TRANSYT-7F and PASSER II, a signal simulation/optimization computer
programs, were used to evaluate system operations and to develop optimized timings.
The major portion of the project consisted of implementing a "closed-loop" traffic signal
system for six (6) signalized intersections along Denton Tap Rd. from parkway Blvd. to
Wrangler. The system was installed by Arjang Electric Systems and Construction, Inc. (Prime
Contractor) and Traconex-Multisonics (System Manufacturer). The system installation
consisted of installing or upgrading six Multisonics 820A controllers, installing a system
master controller, installing approximately 14, 100 linear feet of communications cable (6-Pair
//19 AWG), installing system detectors, and installing a central micro-computer station.
The installed signal system provides a means of coordinating traffic flow with the ability to
monitor and respond to changes on a real time basis. The on-street master controller
manages the functions of the local controller by means of the interconnect cable. The
microcomputer monitors the system operations via a modem and dial-up telephone
communications.
The newly implemented signal system showed an estimated annual reduction of 116,492.00
vehicle-hczurs of delay, 123,984.00 gallons of fuel, and 1,744,500.00 vehicle stops. The
overall annual operating cost savings to the Denton Tap Rd. signal system is projected to be
$1,323,327.00. With a total project cost of approximately $66,007.00, the'resulting benefit
to cost ratio is 20.05.
TABLE OF CONTENTS
PAGE
Executive Summary
List of Tables and Figures ii
1. Introduction 1
Project Background 1
2. Traffic Data Collection 5
Traffic Volumes 5
Signal Phasing and Timing 5
Intersection Geometries 5
Travel Time Data 5
3. Summary of Project Activities I 1
Calibration Study 1 1
Timing Plan Development 1 1
System Implementation and Fine-Tuning 12
4. Resource Analysis Summary 1 3
5. Discussion of Results 14
Overall Improvements 1 4
6. Conclusion 1 6
LIST OF TABLES
PAGE
1. Summary of Project Activities 1 2
2. Summary of Resource Requirements 13
3. Summary of Improvements 1 5
LIST OF FIGURES
PAGE
1. TLS Project Study Limits 2
2. Intersection Identifications and Link Distances 4
3. Average Daily Traffic Denton Tap Road 6
4. AM Peak Hour Traffic Volumes 7
5. Noon Peak Hour Traffic Volumes 8
6. PM Peak Hour Traffic Volumes 9
7. Existing Lane Configurations 10
INTRODUCTION
The Traffic Light Schronization Program II (TLS II) is a State grant program funded under the
Oil Overcharge Restitutionar¥ Act and administered by the Texas Department of
Transportation (TxDOT). The purpose of this program is to reduce vehicle stops and delays,
save fuel, and reduce vehicle emissions by providing funding assistance to cities for traffic
signal improvements. Nationwide experience has shown that one of the greatest benefits to
the public for each dollar spent on traffic operations come from traffic signal timing and
coordination improvements.
The purpose of this report is to summarize the findings of a signal retiming and signal system
implementation project in the City of Coppell, Texas. This study has been conducted in
conjunction with the Texas Department of Transportation's Traffic Light Synchronization
Program. The study area is shown in Figure 1.
PROJECT BACKGROUND
The Governor's Energy Management Center (GEMC) and the Texas Department of
Transportation (TxDOT) sponsored the TLS Program because of increasing concern over the
consumption of fuel by motor vehicles on city streets. The GEMC estimates that statewide
application of improvements in traffic signal retiming could reduce fuel consumption
significantly. In an effort to demonstrate the effectiveness of signal timing optimization in the
conservation of fuel, the GEMC initiated the TLS Program, to be administered through TxDOT.
TxDOT secured the services of the Texas Transportation Institute (TTI) to assist cities and
counties in this program and provide training.
The City of Coppell was selected as one of the cities to receive assistance in implementing
and evaluating the PASSER II and TRANSYT-7F optimization models. The City of Coppell and
Barton-Aschman Associates, Inc. have worked with TxDOT and TTI to carry out the project
tasks and have been successful in demonstrating the benefits of signal system and signal
timing improvements.
NETWORK DESCRIPTION
The City of Coppell enjoys the distinction of being the second fastest growing community in
North Central Texas over the past ten years and the fastest growing among cities having a
population of 10000 or greater. To go along with this growth, there has been a steady
growth in traffic volumes coupled with shifting travel patterns as new streets are constructed
improved and/or extended.
In order to better accommodate the increasing traffic volumes and changing traffic patterns,
this project was undertaken to improve traffic signal operations along a major arterials, Denton
Tap Road, and at several key intersections. Figure 2 shows the location of the study
intersection, link distances between intersections and intersection study node designations.
All of the intersections are isolated and run "free" throughout the day.
PROPOSED SYSTEM IMPROVEMENTS
The City of Coppell proposed to initiate progression along Denton Tap Road by coordinate the
timing plans at each intersection through the implementation of a closed-loop system. In
order to implement this system, the addition of a microcomputer station with printer, 6-pair
//19 AWG cable, and controller upgrades were proposed.
The extension of MacArthur Boulevard propagated the need to retime the intersection of
Sandy Lake Road and MacArthur Boulevard. To upgrade the operation at this intersection to
fully actuated, a new eight phase, solid state controller was proposed. The two study
locations on Belt Line Road were investigated to determine if they would benefit from time
based coordination (TBC).
The overall objectives of the project are listed below:
1. Provide improved progression.
2. Reduce delay, stops and fuel consumption at the study intersections.
3. Develop signal timing plans using the PASSER II and TRANSYT-7F traffic signal
optimization computer programs.
4. Evaluate the effectiveness of the revised signal timing plans in reducing delay,
stops and fuel consumption.
5. Raise the consciousness of citizens, public officials, and transportation
engineers concerning the importance of modern computerized signal timing
design techniques and signal system technology for use in reducing delay,
stops, and fuel consumption.
Plrkway Blvd.
Not to
S.ndy L.ke Rd. I(~
t, /~P Sandy L-ke Rd.
Bethel School Q
Bethel I~ 2.700'
_
FIGURE 2
INTERSECTION IDENTIFICATIONS
AND LINK DISTANCES
~ .
TRAFFIC DATA COLLECTION
As part of this study, twenty-four hour counts, peak hour turning movement volumes, field
measurements of signal phasing and timing, and network travel time data 'were collected.
This data was collected to evaluate and calibrate "Before" and "After" conditions. TRANSYT-
7F, a signal timing simulation/optimization computer program, was utilized to evaluate the
operating characteristics of the network.
TRAFFIC VOLUMES
Twenty-four (24) hour counts were conducted on Denton Tap Road to define traffic patterns
and daily traffic variations. These counts are illustrated in Figure 3. The A.M., Noon, and
P.M. peak hour turning movement traffic volumes were collected during March 1992. The
A.M., Noon, and P.M. peak hour volumes are shown in Figures 4, 5, and 6, respectively.
SIGNAL PHASING AND TIMING
Signal phasing and timing information for each study location was verified by field
measurements. For all actuated locations, analysis timing parameters were based on averages
taken from field measurements.
INTERSECTION GEOMETRIES
Figure 7 illustrates the intersection approach configurations and lane assignments for each
study location. The saturation flows used in the TRANSYT-7F models were derived from the
diagrams.
TRAVEL TIME DATA
The network travel time data was collected in the field using the floating car technique to
establish flow characteristics and to serve as a basis for calibrating the analysis model for the
"Before" and "After' conditions. Travel time runs were conducted along Denton Tap Road for
the A.M., Noon, and P.M. peak periods in both directions. Four (4) to six (6) runs were
conducted in each direction during each study period.
141
c~ e I Not to Bc~le
Jl! .~--165
$1ndy Leke Rd. /f~, /-343 _//~/~ /f'1~"116 ~ndy Lnke RcL
145.-.~ 21._~
111'~
i
Jl. ll-,,-28
Bethel Bchool )'T",
36 -,(
106-, !
39'~
WrInkler ~
FIGURE 4
AJ~. PEAK HOWl TRAFFIC VOLUMEO
~,
I
Not to So~le
,.,~., ~0~oo,
Bethel 12~
32~
25
10-~
FIGURE ~
NOON PEAK HOUR TRAFFIC VOLUMES
[~ ·
~ ~ Not to 8c~le
~221 ~ ~e Rd.
Bethel School 41~1~1/ ~
/1/
102~
FIGURE 6
P.M. PEAK HOUR TRAFFIC VOLUMES
Wr&n~ller
' FIGURE 7
EXISTING LANE CONFIGURATIONS
3.
SUMMARY OF PROJECT ACTIVITIES
Several tasks were completed during this project including collection of traffic data (see
_ previous section for summary), calibration of "Before" and "After" conditions using TRANSYT-
7F, installation of new traffic signal system control equipment, optimization of peak period
timing plans, implementation of optimized timing plans, and fine tuning of implemented signal
timings.
CALIBRATION STUDY
"Before" and "After" calibration studies were conducted to check the validity of TRANSYT-TF
in replicating actual field measurements. The existing peak period turning movement volumes,
saturation flow rates, signal phasing and timing were input in the TRANSYT-7F model to
simulate "Before" and "After" conditions.
To calibrate TRANSYT-7F, the observed or measured travel time was compared to the travel
times predicted by the computer program. The travel times calculated by the program consist
of the running time between intersections and the average delay incurred at each of'the
intersections. The desired goal was to have less than twenty percent (20%) difference
between the observed and simulated travel time values. The calibration results are included
in the Appendix.
TIMING PLAN DEVELOPMENT
Optimized signal system timing plans were developed using PASSER II. PASSER II was used
to generate timing plans with optimal bandwidths. Three (3) timing plans ere developed for
the Denton Tap Road to address the AM peak, Noon peak, and PM peak traffic conditions.
Based on field observations, timing plan evaluations, and the fine-tuning effort, it was
determined that the Denton Tap Road system operates more efficiently during the non-peak
periods in a "free" or fully actuated mode under current traffic conditions. The final optimized
timing plans for the AM peak and PM peak utilizes cycle lengths of 80 seconds and 85
seconds, respectively.
11
-- SYSTEM IMPLEMENTATION AND FINE-TUNING
Table 1 presents a summary of the project activities for the Denton Tap TLS project.
TABLE 1
SUMMARY OF PROJECT ACTIVITIES
Time Period Activity
March 1992 Initial Data Collection
June 1992 Before Study Evaluation
June 1992 - November, 1992 Design and Preparation of PS&E
November, 1992 Timing Plan Development
November, 1992 Bid Procurement
November 18, 1992 Award of Construction Contract
January, 1993 - February, 1993 Signal System Installation
March - April, 1993 Timing Implementation and Fine-Tuning
April, 1993 System Training
May, 1 993 After Study Evaluation
12
m
RESOURCE ANALYSIS SUMMARY
Approximately 500 person-hours (City and Consultant personnel) were estimated as needed
to complete this project. These estimated hours included time spend acquiring PASSER II and
TRANSYT-7F, learning to use both programs, collecting the data, calibrating the model,
designing the system, optimizing the signal timing, implementing the signal system,
implementing and fine-tuning the timing plans, and preparing the "Before" and "After" studies.
The total estimated project cost was $66,007.30. The resource analysis summary is
presented in Table 2.
TABLE 2
SUMMARY OF RESOURCE REQUIREMENTS
Cost Type Level/Type Time (Hours) Cost
City Personnel Engineering 180 $ 3,604.80
Technical/
Clerical
City Cost Equipment $2,122.00
Contractor Construction/
Installation $ 38,205.50
Consultant Engineering 320 $22,075.00
TOTAL PROJECT COST $66,007.30
13
m
DISCUSSION OF RESULTS
Overall Improvements
The estimated benefits resulting from the signal system improvements are presented in table
3. Table 3 summarizes the TRANSYT-7F output with respect to fuel consumption, total
delay, and total stops for the network. The hourly values were annualized over 3090 days
assuming a 12-hour day. The calculations were based upon a 2-hour AM peak, a 2-hour PM
peak and a 8-hour Off/Noon peak. To calculate annual operating costs, fuel was valued at
$1.00 per gallon, delay was valued at $10.00 per vehicle-hour, as stops were valued at
$0.014 per vehicle stops. The annual operating cost savings are also shown in table 3.
The total annual cost savings due to the traffic signal system improvements were estimated
to be $1,323,327.00. When compared to the total project cost of $66,007.30, the resulting
benefit to cost ratio is 20.05 to 1. The reduction in British Thermal Units (BTU) was
estimated by multiplying the reduction in fuel consumption by 126,000 and was calculated
to be 16 billion BTU's per year.
ANALYSIS OF FIELD MEASUREMENTS
Test car travel time studies were made on Denton Tap Road, both before and after the signal
system improvements were made. The results of the field measurements were consistent
with the TRANSYT-7F model in demonstrating and evaluating the signal system
improvements. Due to the limited sample sizes, no statistical comparisons were made.
14
m
CONCLUSIONS
The City of Coppell's Traffic Light Synchronization Program II project resulted in a cost-
effective effort. The following list summarizes the conclusions of the study:
· Fuel consumption was reduced by an estimated 123,984 gallons per year
· Total system delay was reduced by 117,492 vehicle-hours per year
· The number of vehicle stops was reduced by an estimated 1,744,500 vehicle stops
· A total annual operating cost savings of $1,323,327.00 is projected as a result of the
signal system improvements.
The total cost of the project was approximately $66,007.00 which corresponds to a
benefit to cost ratio of 20.05
16
APPENDIX
17
A. BEFORE STUDY MEASURES OF EFFECTIVENESS
COPPELL TLS II PROJECT
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
1 Denton Tap/Parkway 49.46 28.65 1756.6
2 Denton Tap/Sandy Lake 95.91 45.46 2034.2
3 Denton Tap/Bethel School 81.03 15.64 1997.9
4 Denton Tap/Bethel 59.56 6.93 1444.6
5 Denton Tap/Belt Line 138.87 71.92 2199.2 --
6 Denton Tap/Wrangler 78.22 53.70 865.9
7 Belt Line/Moore 43.50 8.62 1008.4
8 Belt Line/Mockingbird 37.85 13.56 1046.4
9 MacArthur/Sandy Lake 39.01 20.03 1826.7
TOTAL 623.41 264.51 14179.9
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
1 Denton Tap/Parkway 11.49 1.75 341.6
2 Denton Tap/Sandy Lake 36.90 6.45 1080.0
3 Denton Tap/Bethel School 93.96 68.88 1079.8
4 Denton Tap/Bethel 30.97 5.59 565.2
5 Denton Tap/Belt Line 42.06 2.56 756.7
6 Denton Tap/Wrangler 19.10i 1.88 439.2
7 Belt Line/Moore 16.61 1.31 257.5
8 Belt Line/Mockingbird 10.02 1.15 347.0
9 MacArthur/Sandy Lake 13.35 5.41 673.7
TOTAL 274.46 94.98 5540.7
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
1 Denton TaD/Parkway 44.68 8.15 1326.4
2 Denton Tap/Sandy Lake 77.97 18.23 2104.3
3 Denton Tap/Bethel School 72.30 14.62 2074.81
4 Denton Tap/Bethel 118.71 104.94 913.7. .-
5 Denton Tap/Belt Line 92.93 25.70 2122.6 .,
6 Denton Tap/Wrangler 26.23 4.51 986.8
7 ~Belt Line/Moore 43.89 8.78 1030.5
8 Belt Line/Mockingbird 18.14 2.83: 705.8
9 MacArthur/Sandy Lake 33.22 17.10 1554.0
TOTAL 528.07 204.861 12818.9
B. AFTER STUDY MEASURES OF EFFECTIVENESS
COPPELL TLS II PROJECT
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
I Denton Tap/Parkway 41.90 15.92! 1692.9
2 Denton Tap/Sandy Lake 83.72 35.73 1765.0
3 Denton Tap/Bethel School 82.16 16.07 2157.0
4 Denton Tap/Bethel 51.79 10.88 621.7
5 Denton Tap/Belt Line 72.57 13.33 1964.7 --.-
6 Denton Tap/Wrangler 75.34 54.69 627.5
7 Belt Line/Moore 43.50 8.62 1008.4
8 Belt Line/Mockingbird 37.85 13.56 1046.4
9 MacArthur/Sandy Lake 39.01 20.03 1826.7
TOTAL 527.84 188.83 12710.3
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
I Denton Tap/Parkway 11.49 1.75 341.6
2 Denton Tap/Sandy Lake 36.90 6.45 1080.0
3 Denton Tap/Bethel School 93.96 68.88 1079.8
4 Denton Tap/Bethel 30.97 5.59 565.2
5 Denton Tap/Belt Line 42.06 2.56 756,7
6 Denton Tap/Wrangler 19.10 1.88 439.2
7 Belt Line/Moore 16.61 1.31 257.5
8 Belt Line/Mockingbird 10.02 1.15 347.0
9 MacArthur/Sandy Lake 13.35 5.41 673.7
TOTAL 274.46 94.98 5540.7
PEAK HOUR
Fuel Total Uniform
Consumption Delay Stops
Node Intersection (Gal/Hr) (Veh-Hr/Hr) (Veh/Hr)
1 Denton Tap/Parkway 44.53 8.86 1220.4
2 Denton Tap/Sandy Lake 75.62 18.11 1857.5
3 Denton Tap/Bethel School 59.30 9.44 1316.7
4 Denton Tap/Bethel 56.54 10.14 1507.5, .-
5 Denton Tap/Belt Line 68.74 12.63 1800.9 -.
6 Denton Tap/Wrangler 17.02 1.83 388.3
7 Belt Line/Moore 43.89 8.78 1030.5
8 Belt Line/Mockingbird 18.14 2.83 705.8
9 ,MacArthur/Sandy Lake 33,22 17.10 1554.0
TOTAL 417.00 89.72 11381.6
TABLE C. TRANSYT-7F CAUBRATION SUMMARY
BEFORE STUDY
Percent
- Total Total Difference
Observed TRANSYT-7F Between
Travel Time Travel Time 'FTF and
Arterial Direction Period (Sec/Veh) (Sec/Veh) Observed
Denton Tap Rd. NB AM 280.67 289.24 3.05%
Denton Tap Rd. SB AM 260.00 276.70 6.42%
- Denton Tap Rd. I NB NOONI 260.33I 254.50I 2.24%
Denton Tap Rd. SB NOON 272.84 234.71 13.98%
_ Denton Tap Rd. NB PMI 266.50 317.53I 19.15%
Denton Tap Rd. SB PM 268.33 279.31 4.09%
.~,FTER STUDY
Percent
Total Total Difference
Observed TRANSYT-7F Between
Travel Time Travel Time ~TF and
Arterial Direction Period {Sec/Veh) {Sec/Veh) Observed
Denton Tap Rd. NB AM 280.67 255.821 8.85%
- Denton Tap Rd. SB AM 260.00 271.48 4.42%
Denton Tap Rd. SB PM 268.33 280.94 4.70%