ST9002-SY 891208_ 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
_ (~14) 748-67~0
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
Freeway Parkway. These two developments, by virtue of their
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 Fe Pacific 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
counts, thoroughfare plan and year 2010 traffic
projections.
BETHEL
o
~ SlL & SW RR
SOUTHWESlERN BELT LINE
AIRLINE
· ' ;OWBOY
z
FIGURE 1
Proposed Prentiss Properties and
Santa Fe Pacific Realty Developments
-- 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 ALIGNMENTS
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.
-- 3
BETHEL
0
rr STL & SW RR
.... BELT LINE
VINE CREEK
AIRLINE
COWBOY
LI
FIGURE 2
Alternative 1
BETHEL
7
0
0
UJ
0
o: STL & SW RR
~mmmmmm ESTERN BELT LINE
IIImlllllll'
CREEK
~ ......... A~RLINE
COWBOY
uJ
FIGURE 3
Alternative 2
BETHEL
Q-
Z
0
n- STL & SW RR
llIH~lHHH~l I'll~,,ll~ ESTERN BELT LINE
I~II~*%~ CREEK
~RLINE
COWBOY
FIGURE 4
Alternativ® 3
BETHEL
O
Z
STL & SW RR
.- . ........ illllll.llllllll IIIIII THWESTERN BELT LINE
GATEWAY CREEK
[llllllllllllllll
°% ' - . AIRLINE
COWBOY
LLJ
FIGURE 5
Alternative 4
PROJECTIONS
-- Year 2010 peak hour traffic volume projections for the study
area were developed through a four-step traffic modeling
procedure:
_ 1. Estimate 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 the "base" volumes from step #2 to the site-
generated 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 per the submitted site plans.
Details of this procedure are described below.
Year 2010 24-Hour Base Volumes
Information assembled for this stage of the subarea traffic
modeling procedure consisted of:
o Available daily traffic counts. DeShazo, Starek &
Tang performmed 24 hour machine counts on Royal Ln and
_ Freeport Pkwy. south of Bethel Rd., and on Bethel Rd.
east and west of Freeport Pkwy. Manual turning
movement counts were performed at the intersection of
Belt Line and Denton Tap Rd. from 7-9 AM and 4-6 PM to
- determine morning and evening peak hour turning
movement volumes.
8
-- o Population and employment estimates, by traffic survey
for 1986 and 2010 prepared by the North Central Texas
Council of Governments (NCTCOG).
o Year 2010 daily traffic volume estimates obtained from
the "20-20-27" traffic model developed by the State
Department of Highways and Public Transportation
-- (SDHPT).
o Year 2010 dily traffic volume estimates obtained from
_ NCTCOG's MTAP (Multi-modal Transportation Analysis
Process) traffic model.
o Thoroughfare plans for the City of Coppell.
- Estimated current 24 hour traffic volumes are shown in
Figure 6, the Belt Line/Denton Tap peak hour turning
- movement counts are shown in Figure 7 . NCTCOGts population
and employment estimates for the year 2010 were used in both
the SDHPT and NCTCOG traffic models. Estimates for the City
_ of Coppell as submitted by NCTCOG were as follows:
1986 2010
Population 10,800 31,700
- Employment 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 a worst-case forecast scenario.
BETHEL 4000 2000
z
0
STL & SW RR
~U~HWESTERN BEL~ LINE
~0oo ~oo0
~RLINE
COWBOY
FIGURE 6
Estimated Current 24 Hour Volumes
~.M. PEAK HOUR
4 145
112 ~ ~ 68
STE
287
-- 36 197
_ P.M. PEAK HOUR
-- 2
67
330
BELT LINE
62 ~ -m----- 116
iOUTHWESTE!
1109
59 257
FIGURE 7
- AM and PM Peak Hour Turning Movement Counts
at Belt Une/Denton Tap Intersection
BETHEL
F-
O
rr STL & SW RR
.... I~O0 BELT LINE
., 2,~00 VINE CREEK
3000
lllllllllllllllllll _ltlllllllllllll
·
AIRLINE
COWBOY
FIGURE 8
Alternative 1, Year 2010 24 Hour Base Volumes
BETHEL
7
STL & SW RR
~' ~ [STERN BELT LINE
CREEK 11000
5500 :
~ ......... AJRLINE
COWBOY
FIGURE 9
Alternative 2, Year 2010 24 Hour Base Volumes
BETHEL
Z
Q.
0
rr STL & SW RR
ESTERN BELT LINE
0~;~), m m m mlmm m mmmmmmmmmmmmmm, ,,mmmmmm mmmmmmmmmml
CREEK
AIRLINE
COWBOY
FIGURE 10
Alternative 3, Year 2010 24 Hour Base Volumes
BETHEL
Z
Z
0
o:: STL & SW RR
..... mmmmmmmmmmmmm mlmml 'HWESTERN BELT LINE
.... .- ' ~'i 5'6 .oo .~ ,ooo m~['~"'""
GATEWAY CREEK
l'Jlllllllllllllll
· 2300
~'*'" ,..AIRLINE
COWBOY
FIGURE 11
Alternative 4, Year 2010 24 Hour Base Volumes
BETHEL
Q.
Z
0
0
.j
0 u_
rr STL & SW RR
' '"~n I'~ BELT LINE
250
VINE CREEK
$00
:'""'""'"'"'"
AJRLINE
,_, COWBOY
FIGURE 12
Alternative 1, Year 2010 PM Peak Hour Base Volumes
BETHEL
2'
UJ
012
STL & SW RR
IIIIIII II STERN BELT UNE
~II$~IIBi$1
CREEK 1100
iiiIIIl~lllllllll
550 ·
~,, ........ AIRLINE
COWBOY
Z
FIGURE 13
Alternative 2, Year 2010 PM Peak Hour Base Volumes
BETHEL
z
0 "
~ STL & SW RR
mmmmmmmmmmmmmmml mmmmmmmm ESTERN BELT LINE
mlllllllll!
110o
CREEK
AIRLINE
COWBOY
FIGURE 14
Alternative 3, Year 2010 PM Peak Hour Base Volumes
BETHEL
(3_
7
0
UJ
STL & SW RR
~(~)'"?""" "..... HWESTERN BELT LINE
.' GATEWAY CREEK
AJRLINE
COWBOY
LU
FIGURE 15
Alternative 4, Year 2010 PM Peak Hour Base Volumes
TABLE I
PRENTISS PROPERTIES SITE
TRIP GENERATION
PM PK HR TRAFFIC
BUILDING USE AMOUNT IN OUT TOTAL
1 WAREHOUSE 140,800 52 89 141
2 WAREHOUSE 179,200 67 114 181
3 WAREHOUSE 80,000 29 49 78
4 WAREHOUSE 82,000 30 50 80
5 WAREHOUSE 175,000 65 111 177
6 WAREHOUSE 175,000 65 111 177
7 WAREHOUSE 132,000 49 83 132
8 WAREHOUSE 132,000 49 83 132
9 WAREHOUSE 133,000 49 84 133
10 WAREHOUSE 133,000 49 84 133
11 WAREHOUSE 132,000 49 83 132
12 WAREHOUSE 132,000 49 83 132
13 WAREHOUSE 156,000 58 99 157
14 WAREHOUSE 150,000 56 95 150
15 WAREHOUSE 135,360 50 85 135
16 WAREHOUSE 136,000 50 86 136
17 WAREHOUSE 194,000 73 124 197
18 WAREHOUSE 150,000 56 95 150
19 WAREHOUSE 160,000 60 101 161
20 WAREHOUSE 134,000 49 84 134
21 WAREHOUSE 135,000 50 85 135
22 WAREHOUSE 130,000 48 82 129
23 WAREHOUSE 194,000 73 124 197
24 WAREHOUSE 140,000 52 88 140
25 WAREHOUSE 122,000 45 76 121
26 WAREHOUSE 156,000 58 99 157
27 WAREHOUSE 145,000 54 91 145
28 WAREHOUSE 170,000 63 108 172
29 WAREHOUSE 105,000 38 65 103
30 WAREHOUSE 105,000 38 65 103
31 WAREHOUSE 78,000 28 48 76
32 WAREHOUSE 100,000 36 62 98
33 WAREHOUSE 112,500 41 70 111
TOTAL= 4,533,860 1,677 2,855 4,532
O1 OFFICE 231,000 63 331 394
02 OFFICE 258,000 69 363 432
03 OFFICE 107,500 33 176 209
04 OFFICE 82,000 27 140 167
05 OFFICE 143,500 42 223 266
06 OFFICE 151,700 45 234 278
07 OFFICE 168,000 48 254 303
TOTAL= 1,141,700 328 1,721 2,049
SITE TOTAL= 5,675,560 2,005 4,577 6,581
- TABLE II
SANTA FE PACIFIC SITE
TRIP GENERATION
PM PK HR TRAFFIC
PARCEL USE AMOUNT IN OUT TOTAL
SF1 OFFICE 379,894 667 1523 2,190
109.2 AC WAREHOUSE 1~508,616
-- SF2 OFFICE 90,451 159 363 522
26.0 AC WAREHOUSE 359,194
SF3 OFFICE 123,500 217 495 712
35.5 AC WAREHOUSE 490,438
SF4 OFFICE 116,542 205 467 672
-- 33.5 AC WAREHOUSE 462,808
OFFICE 710,387
- WAREHOUSE 2,821,056
SITE TOTAL= 3,531,443 1,248 2,848 4,096
Manual adjustments were made to the computer estimates to
- reflect traffic model errors related to large analysis zones
and inadequate approach links.
_ The resulting year 2010 24 hour base volumes for each
alternative alignment are shown in Figures 8 through 11,
- respectively. The critical design hour for commercial
development is typically the p.m. peak hour. 24 hours
volumes are multiplied by 10% to estimate "peak hour"
volumes. The estimated year 2010 p.m. peak hour base
traffic volumes for each alternative alignment are shown in
Figures 12 through 15, respectively.
TRIP GENERATION
The site generated traffic for the proposed developments is
shown in Table I and II. The trip generation rates used are
from the Institute of Transportation Engineers Trim
Generation Manual. The proposed Prentiss Properties
- development conceptual plan shows thirty three warehouse
buildings averaging 140,000 s.f. each, for a total of
4,533,860 s.f of warehouse. Seven office buildings were
_ shown, averaging 163,000 s.f., for a total of 1,141,700 s.f
office. The total site square footage is estimated to be
-- 5,675,560 s.f.. The Santa Fe Pacific development plan does
not specify buildings and usage, but a similar density of
warehouse and office hase been suggested, therefore the
traffic generated on the Prentiss Properties site is
factored down by area on each of the Santa Fe Pacific
_ parcels. To account 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.
TRIP DISTRIBUTION
After performing trip generation, the trips resulting from
the proposed developments are distributed to the area street
system. Figure 16 shows the orientations used for
distribution. Figures 17 through 20 show the development
traffic on each alternative alignment, respectively.
- Figures 21 through 24 show the sum of the 2010 pm base plus
site traffic on each alignment, respectively.
7% 3%
BETHEL
3%
7
0
I--
i-. z
0 cb
LU
STL & SW RR
SOUTHWESTERN
L.8 BELT LINE
AIRLINE
COWBOY
· 5%
FIGURE 16
Directional Distribution
35%
5%
BETHEL
O.
Z
0
o
0 u_
o:: STL & SW RR
· ' '~ ~'~ ~00 BELT LINE
o° VINE CREEK
60O
_.mlllllllllllllll t
% !l~''" GATEWAY
132' 1312
COWBOY
uJ
FIGURE 17
Alternative 1, Alternative I PM Peak Hour Site Traffic
BETHEL
Z
7
O~
UJ
rr STL & SW RR
ESTERN BELT LINE
IIIIIIIIIII~
CREEK 888
493 1189
i....~.1.1..., NRLINE
COWBOY
FIGURE 18
Altemative 2, PM Peak Hour Site Traffic
BETHEL
uJ
STL & SW RR
%
152~ 1512
COWBOY
FIGURE 19
Alternative 3, PM Peak Hour Site Traffic
BETHEL
Z
uJ
a: STL & SW RR
.....- .... ~-~" "~-~".."~W-~' ';~'~ ',,,E~T~,~, 8EL, L,~,E
GATEWAY ;REEK
~llllllllllllll~ll
. 600
'~'** ............... AIRLINE
511
'152~
COWBOY
Oo
i.u
FIGURE 20
Alternative 4, PM Peak Hour Site Traffic
BETHEL
STL & SW RR
,, ~3~ ' ' '1¥~ D' BELT LINE
VINE CREEK
lllll~l'~l~ GATEWAY
'"- .... .s.!l.. '~RUNE
1312
COWBOY
z
FIGURE 21
Alternative 1, Year 2010 PM Peak Hour Base + Site Traffic
BETHEL
O_
Z
Z
-J uJ
0 u_
rr STL & SW RR
ES/ERN BELT LINE
IIIIllllllm
CREEK 1988
1043 1689
IIIl~lllllIlII
1524 1512
COWBOY
FIGURE 22
Alternative 2, Year 2()10 PM Peak Hour Base + Site Traffic
BETHEL
Z
0
Z
0
o: STL & SW RR
ESTERN BELT LINE
· ~e~aa~,, ~, CREEK
1524 1512
COWBOY
FIGURE 23
Alternative 3, Year 2010 PM Peak Hoa' Base + Site Traffic
BETHEL o_
Z
o
0
rr STL & SW RR
,IIIIIllI.IIIIi rHWESTERN
2077 198§' BELT LINE
....-- ..... §'d{~"
:
GATEWAY ;REEK
%° ' .,.. AIRLINE
511
1524 1512
COWEK)Y
FIGURE 24
Alternative 4, Year 2010 PM Peak Hour Base + Site Traffic
_ ALIGNMENT CHARACTERISTICS
Alternative 1:
-- o Provides for through movement from Belt Line Rd. to
Royal Ln.
_ o Additional collector roadway provides interior
circulation.
o Horizontal alignment of Gateway is straighter and would
- allow higher design speeds.
o Gateway Blvd. in conjunction with Grapevine Creek
- greatly impairs the ability to develop warehouse-type
uses due to its close proximity to the RR tracks, and
the need to provide RR access would require numerous
_ crossings.
o This alternative is costly because of two major
crossings of Grapevine Creek.
o Bethel and Gateway form one east/west corridor, and
gateway and I.H. 635 form another east/west corridor.
_ In the Bethel/Gateway corridor the STL & SW RR tracks
form a major barrier.
o As presently layed out heavy interior site truck
-- traffic will load on Gateway intermixing with through
traffic thereby impeding the through movement.
- o The close proximity of the Gateway/Southwestern
intersection to the Gateway/Belt Line intersection
reduces the capacity of Gateway Blvd.
Alternative 2:
o Provides direct through movement from Royal Ln. to Belt
- Line.
o More economical in that it only has one crossing with
_ Grapevine Creek.
o The alignment of Southwestern provides a buffer between
the existing land 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.
o This alignment provides for better utilization of land
in developing efficient site development plans.
Alternative 3:
_ o Provides the most direct route from Belt Line to Royal.
o More economical in that it only has one crossing with
Grapevine Creek.
o The alignment of Southwestern provides a buffer between
the existing land uses to the north and the proposed
future land uses to the south.
o Greatly impacts the Santa Fe tract in that it makes the
development of warehouse uses extremely difficult.
o The need to provide RR access would require
numerous crossings to serve warehouse uses south of the
_ road.
Alternative 4=
- o Provides least capacity of all alternatives and reduces
the ability to carry through movements from Royal to
Belt Line.
o This type of thoroughfare plan is inefficient in terms
of land development.
o In Santa Fe tract numerous rail spur crossings along
the northernmost collector would occur.
-- CONCLUSION
Due to the detriment to the Santa Fe tract, Alternatives 3
and 4 are less acceptable alternatives. They impact the
ability to develop the land efficiently and encourage
numerous spur rail crossings and in the case of Alternative
4, provides less roadway capacity capabilities. S~arizing
the differences between Alternative 1 and 2, Alternative 2
- provides a more acceptable alignment to Alternative 1 due to
the following reasons:
o Provides an alignment that is more conducive to a site
development plan.
- o Provides more capacity to through movements by limiting
the amount of local traffic, particularly truck traffic
that would use this street for interior circulation.
o Less costly, only requires one creek crossing.
_ o Alternative 2 in conjunction with the RRtracks
provides a buffer between the land uses to the north
and the proposed land uses to the south.
- o Has less impact on the Denton Tap/Belt Line
intersection due to better distribution of interior
site generated 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 route supported by Prentiss Properties and Santa
Fe Pacific Realty.
35