Item 4CCITY OF
SOUTHLAKE
MEMORANDUM
(February 21, 2012)
To: Shana Yelverton, City Manager
From: Robert H. Price, P.E., Public Works Director
Subject: Approve a professional services agreement with Kimley-
Horn and Associates, Inc. for design services for the FM
1709 Traffic Signal Timing Study project in the amount
of $71,200
Action
Requested: Approve a professional services agreement with Kimley-
Horn and Associates, Inc. for design services for the FM
1709 Traffic Signal Timing Study project in the amount of
$71,200
Background
Information: TxDOT construction of the FM 1709 Median and
Deceleration Lane project began in November 2010.
Construction is still on- going. Raised medians have been
installed from Pearson Lane to Nolen Drive. Irrigation,
electric, and landscaping work will continue through
completion. Deceleration lane construction is currently on-
going. Anticipated completion of TxDOT's construction is
summer 2012.
With the addition of raised medians and deceleration lanes
along FM 1709 from Pearson Lane to Commerce
Street /Gateway Drive, u -turn and left turn volumes will be
substantially greater at all intersections than they were when
the corridor's traffic signals were re -timed in 2008.
Kimley -Horn and Associates, Inc. (KHA) will develop new
signal timing plans and assist with the implementation and
fine - tuning of the traffic signals at all of the existing
intersections along Southlake Boulevard. The intersections
from west to east are as follows: Pearson Lane, Davis
Boulevard /Randol Mill Road, Peytonville Avenue, Southridge
Lakes Parkway /Waterford Drive, Shady Oaks Drive, White
Chapel Boulevard, Byron Nelson Parkway /Diamond
Boulevard, Carroll Avenue, Central Avenue, Village Center
Drive, Kimball Avenue, Nolen Drive, Commerce
Street /Gateway Drive.
As part of the study, Kimley Horn will obtain the existing
signal timing information from TxDOT, verify intersection
roadway geometry, record traffic counts and turning
movements, and evaluate vehicular and pedestrian
clearance times. The consultant will also accompany TxDOT
personnel as the new timing is implemented and will perform
in the field fine - tuning of the signals. At the end of the
project, the final timing plans and the electronic Synchro
model will be provided to the city and TxDOT.
The current schedule anticipates that construction of both
the medians and the deceleration lanes will be completed by
summer 2012.
Financial
Considerations: Funds for the study are included in the previously approved
Capital Improvements Program project budget. The amount
budgeted for the study was $90,000 from Red Light Camera
funds.
Strategic Link: The FM 1709 Median and Deceleration Lane project links to
the city's strategy map relative to the focus areas of Mobility,
Infrastructure and Performance Management and Service
Delivery. The specific corporate objectives that are met by
the construction of this project include Providing travel
convenience within the City and the region, Providing high
quality customer service, and Investing to provide and
maintain high quality public assets.
Citizen
Input/
Board Review: None
Legal
Review: None
Alternatives: The City Council may approve the Professional Services
Agreement or deny it.
Supporting
Documents: Location Map
Kimley -Horn Agreement
Staff
Recommendation: Approve a professional services agreement with Kimley-
Horn and Associates, Inc. for design services for the FM
1709 Traffic Signal Timing Study project in the amount of
$71,200
Staff
Contact:
Robert H. Price, P.E.,
Gordon J. Mayer, Jr.,
Cheryl Taylor, P.E., C
Public Works Director
P.E., City Engineer
ivil Engineer
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Project Understanding
The Texas Department of Transportation (TxDOT) is currently implementing access
management improvements on FM 1709 within Southlake. The project, which is scheduled to be
completed in March 2012, includes the construction of a raised median. Because of the raised
median, left turns will no longer be possible into or out of driveways and minor cross - streets.
Instead, the traffic that formerly turned left into or out of these driveways will have to make u-
turns at the median openings, almost all of which are at signalized intersections.
Since the combined a -turn plus left -turn volumes will be substantially greater than they were
when this corridor's traffic signals were re -timed in 2008, the City is undertaking this project to
develop new signal timing plans. Because TxDOT will continue to operate and maintain the FM
1709 traffic signals, it is recommended that appropriate TxDOT personnel be involved in the
review process as the new timing plans are developed. Also, it is assumed that the new timing
will be implemented by TxDOT personnel with assistance and support from the Consultant.
Scope of Services
Project Intersections
The project will include developing and assisting with the implementation and fine - tuning of
updated traffic signal timing for the following thirteen (13) existing signalized intersections
( "Project intersections "):
1. FM 1709 & Pearson Lane
2. FM 1709 & Davis Boulevard (FM 1938)
3. FM 1709 & Peytonville Avenue
4. FM 1709 & Southridge Lakes Parkway /Waterford Drive
5. FM 1709 & Shady Oaks Drive
6. FM 1709 & White Chapel Boulevard
7. FM 1709 & Byron Nelson Parkway/Diamond Boulevard
8. FM 1709 & Carroll Avenue
9. FM 1709 & Central Avenue
10. FM 1709 & Village Center Drive
11. FM 1709 & Kimball Avenue
12. FM 1709 & Nolen Drive
13. FM 1709 & Commerce Street /Gateway Drive
The City staff is aware of three (3) additional locations on FM 1709 where traffic signals may be
needed in the future. One is at Jellico Circle/Watermere Drive, which is between the Pearson
Lane and Davis Boulevard signals. Another is about is about 1,200 feet west of the Carroll
Avenue signal. The third location is Meadowlark Lane /Players Circle, which is between the
Peytonville Avenue and Davis Boulevard signals. To the extent practical, this project's new
progression scheme should accommodate future signals at any or all of these locations.
Kickoff Meeting
At the outset of the project, the Consultant will prepare for and attend one kickoff meeting with
the Client to begin the exchange of data to be provided to the Consultant. Also, various policy
issues relative to signal timing will be discussed. Since TxDOT will continue to operate and
maintain the traffic signals, it is assumed that TxDOT personnel will be invited to attend this
meeting. Following the meeting, the Consultant will prepare and distribute a brief memorandum
that summarizes the topics discussed and the consensus that was reached regarding signal timing
policy issues.
Assemble Existing Data
The Consultant will obtain from TxDOT the current local controller and coordination timing for
all project intersections. It is anticipated that this information will be provided in the form of
printouts from the signal system database. This information will need to include the following:
• Local controller timing parameters
o Minimums and maximums
• Vehicular clearances
• Pedestrian timing
• Phase sequences
• Local special functions
• Coordination timing
• Cycle lengths, offsets, splits, and phase sequences
• Time -of -day, day -of -week (TOD/DOW) schedules
• Special events timing
• System- commanded special functions
As available and provided by the Client or TxDOT, the Consultant will also review any relevant
traffic counts made subsequent to the 2008 re- timing project.
Qualitative Assessment
Using personnel experienced in traffic signal operations, the Consultant will perform an in -field
qualitative traffic operations assessment. This will specifically include observing existing cycle
lengths, splits, offsets, phase sequences, and left turn operations modes (e.g., permissive -only,
protected - permissive, or protected - only). The Consultant will also identify by movement any
intersection approaches where excessive queuing is observed, where capacity appears to be
substantially constrained, and /or where excessive delay appears to be the result of inefficient
signal operations. For all Project intersections, the Consultant will also make note of locations
where possible changes in lane assignment may improve intersection operation.
Another item that will specifically be observed is the interaction between u- turning traffic and
traffic making right turns on red.
All Project intersections will be observed during the weekday AM, midday, PM peaks as well as
on Saturday afternoon.
Verification of Arterial and Intersection Geometry and Pedestrian Accommodation
The Consultant will perform a field inventory to collect or verify the following information:
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Project intersections
o Number of lanes and lane use
• Modes of left turn operation
• Existence of push buttons
• Length of left -turn bays
• Crosswalk and stop bar locations
• Arterial segments between project intersections
o Number of lanes
o Posted speed limits
Pedestrian accommodation (for each intersection side)
• Walk/don't walk signals
• Pushbuttons
Traffic Counts
The Consultant will make new recording machine traffic counts as following locations, which
are the same as locations of counts made for the 2008 re- timing project. The data will be
recorded by direction in 15- minute increments and totaled on an hourly basis.
• One (1) 7 -day count will be made between Village Center Drive and Kimball Avenue
• Two (2) 24 -hour weekday counts will be made. One will be west of White Chapel
Boulevard and the other will be west of Jellico Circle
New turning movement counts (TMCs) will be made at all Project intersections for the weekday
AM, Midday, and PM peak periods plus one weekend peak period. The appropriate day
(Saturday or Sunday) for the weekend peak will be determined from the 7 -day counts. For each
peak period, data will be collected for six (6) consecutive 15- minute periods. For each 15-
minute increment, the data will tabulated, by approach direction (e.g., northbound), and by
turning movement (e.g., a -turn, left, straight, or right). The number of pedestrians crossing will
also be tabulated by side of the intersection.
Although the beginning and ending times will be adjusted based on the results of recording
machine counts, the time periods will generally be as follows:
• Weekday AM Peak (typically 6:30 AM to 8:30 AM)
• Weekday Midday Peak (typically 11:30 AM to 1:30 PM)
• Weekday PM Peak (typically 4:30 PM to 6:30 PM)
• Weekend Midday Peak (typically 1:00 PM to 3:00 PM)
Each of the weekday TMCs will be made on a non - holiday Tuesday, Wednesday, or Thursday
when the Carroll ISD schools are in session. The weekend TMC will be made on a weekend
when a holiday does not occur on Saturday or Sunday, the preceding Thursday or Friday, or the
following Monday.
Travel Time Runs
"Before" and "after" travel time runs will be made during each of the four time periods for which
a TMC was made. The one route will be FM 1709 from Pearson Lane to Commerce
Street /Gateway Drive.
During each time period, five runs will be made in each direction. These runs will be made
using "floating car techniques ", i.e. the driver of the test vehicle car to travel at the pace set by
other traffic.
The "before" runs will be made prior to the implementation of any changes to the existing signal
timing. These runs will establish baseline conditions (speeds, delay, and number of stops), to
assist in the determination of appropriate progression speeds, and to identify areas where queue
management is critical and areas where recurrent congestion may affect progressive traffic
movement.
Following the implementation and fine - tuning of the new signal timing, the "after" runs will be
made to quantify the degree of improvement.
Signal Warrant Anal
This scope does not include the performance of signal warrant assessments.
Clearance Interval Calculations
The new 2011 edition of the Texas Manual on Uniform Traffic Control Devices (Texas
MUTCD) became effective on December 8, 2011. That manual includes changes in the
procedures for calculation of vehicular and pedestrian clearance times. As such, for all of the
Project intersection, the Consultant will recalculate the clearance intervals in accordance with the
new Texas MUTCD.
For the vehicular yellows and all -reds, the following ITE formula* will be used:
CP = t + V /(2a ± 64.4g) + (W + L)/V
where:
CP
= non - dilemma change period (yellow plus all -red)
t
= perception- reaction time (nominally 1 second)
V
= approach speed (in ft /sec)
g
= percent grade (positive for upgrade, negative to downgrade)
a
= deceleration rate (ft/sec typically 10 ft /sec
W
= width of intersection, curb to curb (feet)
L
= length of vehicle (feet, typically 20 ft)
* Source: Traffic Engineering Handbook, 6 th Edition, Institute of Transportation
Engineers, Washington, DC 20005, 2009
The following criteria will be used to calculate the proper values for the pedestrian clearance
interval:
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• The assumed walking speed will be 3.5 feet per second unless a different standard
value is mutually agreed upon at the outset of the project
• The distance to be traversed will be from the near curb (or edge of pavement) to the
middle of the far curb, and
• It will be assumed that the end of the calculated pedestrian clearance will be timed
concurrently with the associated vehicular clearance intervals (yellow and all -red).
Number of New Timing Plans
For the entire project area, five (5) new timing plans will be developed:
• Weekday AM Peak
• Weekday Midday Peak
• Weekday PM Peak
• Weekend Peak
• Off -peak
The off -peak timing plan will be intended for use during time periods when traffic volumes are
relatively low but still great enough for coordinated operation to be desirable. Typical times
when this timing plan may be desirable will include weekday mornings between 9 and 11 AM,
evenings between 7 and 10 PM, and certain hours on weekend mornings.
Update SynchroTM Models
The Consultant will update the SynchroTM files of the final (i.e., as- fine - tuned) signal timing
from the 2008 re- timing project. These models will be updated to reflect geometric changes as
well as subsequent timing changes reflected in the data provided by TxDOT. The new TMCs
made for this project will be used to update the traffic volume information. The newly
calculated clearance times will also be incorporated into the models.
The Consultant will then use the following process to calibrate the PM Peak model for existing
peak conditions. The model's link speeds will be adjusted to achieve a reasonable correlation
with actual corridor travel times as determined during the qualitative assessments and the before
travel time runs. The SimTraffic feature will be used to perform a qualitative (i.e., visual)
assessment of the adequacy of the calibration. Specific factors that will be reviewed include
queue lengths and the locations of significant stops and delays. Iterative adjustments will be
made until reasonable calibration is achieved.
Once the "existing" PM peak model has been satisfactorily calibrated, the same procedures will
be used to update and calibrate the "existing" models for the AM, Midday, and Weekend Peak
time periods.
The Synchro model for the off -peak timing plan will be developed using approximately 70
percent of the counted volumes the weekday midday peak. The exact percentage will be based
on factors derived from the 7 -day counts.
Intersection Operations Assessment
During the qualitative assessment and field verification, the Consultant will identify possible
opportunities to improvement intersection operations through lane assignment changes (e.g., by
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changing a straight -only lane to a shared left- through lane). Using the SynchroTM models and
new TMC data, the Consultant will quantitatively assess the benefits of such possible changes.
The Consultant will prepare and submit a brief technical memorandum that discusses the
following:
• Recommended lane assignment changes
• Recommended changes in crosswalk or stop bar locations
Cycle Length Requirements and Control Area Boundaries
Using the SynchroTM models, the practical minimum cycle lengths of the major intersections will
be determined for all four timing plan periods.
For the timing plans developed in 2008, all of the FM 1709 signals in both Southlake and Keller
were part of the same control area. In other words, all of these signals operated at a common
cycle length during each peak period. Having just one control area is desirable since progression
cannot be provided across the boundary between control groups that are operating at different
cycle lengths.
For each of this project's updated timing plans, the intent will be to find one common cycle at
which it is possible for all of the Project intersections to operate. More than one control group
will be assumed to be necessary only if there are substantial differences among the shortest
practical cycle lengths and /or it is not feasible to obtain reasonably good two -way progression
for all intersections at a common cycle length. Also, wherever feasible and appropriate, the intent
will be for this project's new timing plans to interface as smoothly as possible with the existing
coordinate timing at adjacent intersections.
Considering all of these factors, the Consultant will determine the most appropriate control
groups.
Develop Preliminary Timing Plans
Each of the five (5) new timing plans will be developed using the following process.
• Synchro's optimization process will be used to generate a "first cut" version of the timing
plan.
• "On- screen" review and adjustment will then be performed by senior engineers with
extensive experience in traffic signal operations:
o At intersections that are not over - saturated, SynchroTM tends to allocate more time
than necessary to minor movements. Accordingly, the splits for non - coordinated
phases will be reduced to provide additional split times for the coordinated
phases.
o The progression bands will be reviewed and offset will be made to improve
operations for the coordinated movements. Also, to the extent possible without
creating a yellow trap, phase sequence adjustments will be made.
D
For capacity- critical intersections, the Consultant will review the TMC data to determine if
multiple splits appear to be needed. For example, if the peak 15- minute volumes occur at the
same time for all movements, only one split will be presumed to be needed. However, if the
peak 15- minute period for one critical movement occurs substantially earlier or later than the
peak 15- minute period for other critical movements, it may be appropriate for that timing plan to
have more than one split at that intersection.
Develop Preliminary Time -of -Day Schedule
Using the seven -day count data, the Consultant will develop a recommended time -of -day /day -of-
week (TOD /DOW) schedule for operation of the new signal timing plans.
Timing Plan Review Meeting
The Consultant will prepare for and attend up to two (2) meetings in Southlake to review the
proposed timing plans. The Consultant will present the proposed timing plans and TOD /DOW
schedules to the Client and TxDOT. The Consultant will also present recommendations for any
operational changes that appear to be needed due to interactions between a -turns and right turns
on red.
An LCD projector will be used so that the effects of possible timing plan modifications can be
viewed on- screen. Through interactive discussions, consensus will be reached regarding
modifications to be made before the new timing plans are implemented.
Following these meetings, the Consultant will make the agreed -upon modifications and prepare
the timing plan data in the format needed by TxDOT personnel to enter the new timing into the
controllers. This will consist of SynchroTM timing sheet print -outs of the intersection timing
along with a table showing the new time -of -day schedule.
Given the number of intersections and timing plans, it is assumed that not more than two (2)
review meetings will be required to reach consensus regarding the new timing plans.
Timing Plan Data Entry
The actual entry of new timing plans into the controller databases will be done by the TxDOT's
staff. This is typically done by first entering the timing data into a laptop computer. During this
process, the Consultant will provide on -call support to resolve issues that may arise.
Timing Plan Implementation and Fine - Tuning
The Consultant will accompany TxDOT as the new timing is downloaded from the laptop
computer into the controllers. The Consultant will then perform in -field fine - tuning to enhance
the actual on- street operation of the new timing plans. This fine - tuning will be led by senior
engineers with extensive experience in traffic signal operations. It is assumed that TxDOT
personnel will be on -hand to download desired timing adjustments into the controller databases.
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The fine - tuning for the five (5) new timing plans will be performed as soon as practical. If such
fine - tuning is initially performed during the summer of 2012, follow -up fine - tuning will be
performed in early September 2012 after the 2012 -13 Carroll ISD school year has begun.
Final Documentation
Using the same process previously described for the "before" runs, the Consultant will make the
"after" travel time runs. The locations, times -of -day, and number of runs will be the same as for
the "before" runs.
The Consultant will develop a project final report the will include the following;
Executive summary
Narrative discussion of the Project with supporting figures such as maps of the
control groups by time period
Tabular comparisons of the before and after travel time runs
The Consultant will submit a draft version of the final report for review by the Client and
TxDOT. Seven (7) copies will be provided — five (5) for the Client and two (2) copies for
TxDOT. Following receipt of comments, the Consultant will prepare and submit a sealed final
report. Twelve (12) copies will be provided — ten (10) for the Client and two (2) copies for
TxDOT. The Consultant will also provide the Client with a PDF version of the sealed final
report.
The Consultant will provide the Client and TxDOT with documentation of the final (i.e., as fine -
tuned) timing plans. This will be in form of SynchroTM timing sheet print -outs of the final
intersection timing along with a table showing the final time -of -day schedule. For both the
Client and TxDOT, the Consultant will also provide copies of the final SynchroTM electronic
files.