Thoroughfare-SY 891208THOROUGHFARE ALIGNMENT STUDY
FOR SOUTHWESTERN BOULEVARD
IN COPPELL, TEXAS
Prepared for:
Prentiss Properties Limited, Inc.
and
Santa Fe Pacific Realty
Prepared by:
DeShazo, Starek & Tang, Inc.
330 Union Station
Dallas, Texas
(214) 748 -6740.
J89310
December 8, 1989
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THOROUGHFARE ALIGNMENT STUDY
FOR SOUTHWESTERN BOULEVARD
IN COPPELL, TEXAS
Prepared for:
Prentiss Properties Limited, Inc.
and
Santa Fe Pacific Realty
Prepared by:
DeShazo, Starek & Tang, Inc.
330 Union Station
Dallas, Texas
(214) 748 -6740.
J89310
December 8, 1989
INTRODUCTION
Southwestern Boulevard is a collector in west Coppell
between Freeport Parkway and Belt Line /Denton Tap Road.
Prentiss Properties is proposing a Warehouse /Office
commercial development on 328 acres generally bounded by
Southwestern Blvd. to the north, Belt Line Road to the east,
Cowboy Drive to the south and Freeport Parkway to the west.
Santa Fe Pacific Realty is proposing a similar development
on 225 acres located between Royal Lane, the St. Louis &
Southwestern Railroad tracks, LBJ Freeway and both sides of ��`J
Freeway Parkway. These two developments, by virtue of their CCU
size and location have a significant impact on the area
thoroughfares. Conversely, the alignment and sizes of these
thoroughfares) have a significant impact on the site plans of
these developments. The location of the Prentiss Properties
and Santa FePacific developments are shown in Figure 1.
PURPOSE
The purpose of this study is to analyze various alignments
of Southwestern and Gateway Blvd. utilizing predicted year
2010 traffic with the two developments in place. This will
be accomplished in the following steps:
o Obtain current City of Coppell Thoroughfare Plan.
o Obtain ',current year 2010 traffic projections.
o Determine year 2010 base volumes utilizing existing
countso thoroughfare plan and year 2010 traffic
projections.
o Add development traffic to year 2010 base link
volumes;.
o Determine best alignment based on year 2010 link
volumes, impact on site plan, and impact on adjacent
intersections.
In a companion study, roadway sizing will be based on year
2010 link volumes. In a study to follow, horizontal
alignments of roadways built by the developers will be
determined through standards set by the Department of Public
Works.
ALTERNATIVE 4IGNMENTS
Four alternative alignments for Southwestern and Gateway
Blvd. are being studied. Alternative 1 is the City of
Coppell's Thoroughfare Plan alignment, see Figure 2. The
alignment first proposed by Prentiss Properties is shown in
Figure 3. Alternative 3 is a variation of the original
Prentiss alignment. The difference being that as
Southwestern approaches Freeport Pkwy. from Belt Line, it
continues its westerly direction parallel to the RR tracks
rather than veering to the southwest, see Figure 4.
Alternative 4 is similar to the Thoroughfare Plan between
Royal Ln. and Freeport Pkwy., however, east of Freeport the
larger roadway ties into the minor roadway adjacent to the
RR tracks, see Figure 5.
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PROJECTIONS
Year 2010 peak hour traffic volume projections for the study
area were developed through 4 four -step traffic modeling
procedure:
1. Estima a year 2010 24-hour background or "base"
volumes for the study area that assume no develop-
ments on the Prentiss or Santa Fe properties.
2. Calculate year 2010 peak hour "base" volumes that
represent ten percent of the 24 -hour volumes.
3. Calculate year 2010 peak hour volumes that represent
traffic generated by the Prentiss and Santa Fe
properties.
4. Add thje "base" volumes from step #2 to the site -
genera{ed volumes in step #3 to create total year
2010 peak hour traffic volume estimates. This
assumes full buildout of the properties in the year
2010 p{er the submitted site plans.
Details of t1as procedure are described below.
Year 2010 24 -dour Base Voluags
Information assembled or this stage of the subarea traffic
modeling procedure con isted of:
o Available daily traffic counts. DeShazo, Starek &
Tang performmed 24 hour machine counts on Royal Ln and
Freeporlt Pkwy. south of Bethel Rd., and on Bethel Rd.
east agd west of Freeport Pkwy. Manual turning
movement counts were performed at the intersection of
Belt L ne and Denton Trap Rd. from 7 -9 AM and 4 -6 PM to
determine morning and evening peak hour turning
movement volumes.
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• Population and employment estimates, by traffic survey
for 1980 and 2010 prepared by the North Central Texas
Council,of Governmentsl,(NCTCOG).
• Year 20.0 daily traffics volume estimates obtained from
the "20{-20 -27" traffic model developed by the State
Department of Highways and Public Transportation
( SDHPT) .
• Year 200 dily traffic volume estimates obtained from
NCTCOG' MTAP (Multi -modal Transportation Analysis
Process traffic model{
• Thoroughfare plans for the City of Coppell.
Estimated curpent 24 hour traffic volumes are shown in
Figure 6, the!,Belt Line /Denton Tap peak hour turning
movement counts are shown in Figure 7 . NCTCOG's population
and employment estimates for the year 2010 were used in both
the SDHPT andINCTCOG traffic models. Estimates for the City
of Coppell as'submitted by NOTCOG were as follows:
1986 2010
Z p ulation 10,800 31,700
loyment 2,100 6,800
An examination of the year 2010 traffic volume plots
revealed that Prentiss and Santa Fe developments were not
included in the employment forecasts. It was therefore
appropriate to treat these computer estimates as "base" year
2010 volumes that do not represent the traffic generated by
the Prentiss or Santa Fe properties. This was,done in order
to generate 4 worst -case forecast scenario.
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5,675,560 The Santa Fe Pacific development plan does
not specify buildings and usage, but a similar density of
warehouse an4 office has been suggested, therefore the
traffic generated on the Prentiss Properties site is
factored dow� by area on each of the Santa Fe Pacific
parcels. Tollaccount for the impact of site generated truck
traffic, the warehouse volumes are increased 20 %. One truck
is assumed to be equivalent to two passenger cars and
warehouse traffic is assumed to be 20% trucks. This
increase in average projected daily traffic coupled with the
total assumed buildout of the site plans by the year 2010
represent a worst case scenario.
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TRIP DISTRIBUTION
Alter performing trip generation, the tries resultinrs frnm
the proposed ,developments are distributed to the area street
system. Figu )re 16 shows the orientations used for
distribution.:: Figures 17 through 20 show the development
traffic on ea!h alternative alignment, respectively.
71 a l f'ey"ya t ire 4 /y n w►r, ,.�� , ��y .
ALIGNMENT CHA*ACTERISTICS
Alternative 1
o Providesl,for through movement from Belt Line Rd. to
Royal Ln.j
o Additionajl collector roadway provides interior
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circulation.
• Horizontal alient of Gateway is straighter and would
allow higher d sign speeds.
• Gateway Blvd n conjunction with Grapevine Creek
greatly impair, the ability to develop warehouse -type
uses due to it close proximity to the RR tracks, and
the need to pr vide RR access would require numerous
crossings.
• This alternative is costly because of two major
crossings of Grlapevine Creek.
• Bethel and Gateway form one east /west corridor, and
gateway and I. H. 635 form another east /west corridor.
In the Bethel/Gateway cor dor the STL & SW RR track* AAL
form a major bar rie .,._� ,)
• As `presently la ed ut he interior site truck
traffic will to d at ay e n with through
traffic thereby mpeding he t ugh em_,.er�t:
• The close proxi ity of the Gateway /Southwestern
intersection to the Gateway /Belt Line intersection l
reduces the cap city of Gateway Blvd.
Alternative 2:
o Provides direct)
Line.
o More economical)
Grapevine Creek)
through movement from Royal In. to Belt
in that it only has one crossing with
o The alignment o Southwestern provides a buffer between
the existing la d uses to the north and the proposed
future land uses to the south.
o The location of Grapevine Creek to the southeast and
the RR tracks to the north limit the amount of
development in this area thereby increasing the through
movement capacity.
o The alignment of Southwestern will require only one
rail spur crossing between Freeport and Belt Line, and
potentially no crossings west of Freeport.
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o This alignment provides for better utilization of land
in developing efficient site development plans.
Alternative �:
o Providers the most direct route from Belt Line to Royal.
o More economical in that it only has one crossing with
Grapevi a Creek.
o The ali rand ent of Southwestern provides a buffer between
the exi ng land uses to the north and the proposed
future uses to the south.
o Greatly impacts the Santa Fe tract in that it makes the
developlient of warehouse uses extremely difficult.
o The need to provide RR access would require
-numeroug crossings to serve warehouse uses south of the
road.
Alternative 41:
o Provides least capacity of all alternatives and reduces
the abil ty to carry through movements from Royal to
Belt Lin l.
o This typof thoroughfare plan is inefficient in terms
Of land development.
o In Santa Fe tract numerous rail spur crossings
the no ernmost collector would occur.
CONCLUSION
Due to the detriment to the Santa Fe
t
and 4 are less) acceptable alternatives.
v�
act, Alternatives 3 /
They
ability to develop the land efficient encourage
numerous spur frail crossings and in the case of Alternative
4, provides le s roadway capacity capabilities. Summarizing
31
the differences between Alternative 1 and 2, Alternative 2
provides a mo�e acceptable alignment to Alternative 1 due to
the followingjreasons:
o Provides an alignment that is more conducive to a site
developm nt plan.
o Provides more capacity to through movements by limiting
the amou t of local traffic, particularly truck traffic
that would use this street for interior circulation.
o Less costly, only requires one creek crossing.
o Alternati e 2 in conjunction with the RR tracks
provides buffer between the land uses to the north
and the p oposed land uses to the south.
o Has less mpact on the Denton Tap /Belt Line
intersect on due to better distribution of interior
site gene ated traffic between Freeport and Belt Line.
In conclusion Alternative 2 is the more efficient alignment
for Southwestern Blvd. between Royal Ln. and Belt Line Rd.
and is the roue supported by Prentiss Properties and Santa
Fe Pacific Realty.