TRAFFIC IMPACT ANALYSIS


The Westwood Center
Loop 1604 (Leslie Road) @ Culebra Road (FM 471)
San Antonio, Texas

May 3, 2000
E0207300

The Westwood Center area, consisting of 99.156 acres of land, is located at the northwest corner of Culebra Road (FM 471) and Loop 1604 (Leslie Road). The Westwood Center area is dissected by Culebra Creek, resulting in 68.017 acres of developable land north of the creek, fronting along Leslie Road, and 31.139 acres of developable land south of the creek, fronting along Culebra Road.

The same area was included in the Stonebridge POADP, for which a Level 3 TIA report was prepared in January 1997.The Westwood Center portion of the Stonebridge POADP would be the area east of the 135-foot wide CPS transmission easement extending north across Culebra Road, through the Stonebridge area. The 1997 report delineated the 40.6 acres south of the creek to be developed as 30.6 acres of manufactured housing and 10.0 acres of commercial (supermarket) development. The 70.1 acres of land north of the creek were delineated to be developed as 50.1 acres of manufactured housing and 20.0 acres of general commercial (shopping center) development. In January 1999, the TIA report was revised for the 70.1 acres, for the purpose of rezoning a portion of the 70.1 acres. The revised land use was to provide 31.45 acres of manufactured housing and 38.75 acres of commercial development. The revision was to accommodate a large Wal*Mart development at the northeast corner of the property, part of which has been delineated for the manufactured housing development.

PURPOSE

The purpose of this updated traffic impact analysis report is to summarize the trip generation numbers from the existing TIA reports for the Westwood Center portion of the Stonebridge POADP and to enumerate the trip generation numbers and the anticipated trip distribution of the trips generated during the significant peak periods (Weekday AM, Weekday PM, and Saturday Peak) for the most current plan for the 99.156 acres.

The difference between the 99.156 acres of the Westwood Center development and the 100.7 acres of the portion of the Stonebridge POADP is result of the final determination of the limits of the 100-year flood plain of Culebra Creek and the right-of-way of the public roadways in the northern portion of the property (Westwood Loop and Westwood Vista).

STONE BRIDGE TRIP GENERATION

South 40.6 Acres

Based on the applicable reference in 1997, the Fifth Edition of the ITE TRIP GENERATION, the number of trips expected to be generated by a manufactured housing development [ITE Code: 240], consisting of 153 units in a 30.6-acre tract, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per unit 4.81 0.40 0.56 >0.43 0.58 3.43 0.54
%enter/%exit 50%/50% 21%/79% 62%/38% 26%/74% 62%/38% 50%/50% 53%/47%
Total Trips 736 61 86 66 89 525 83
Enter/Exit 368/368 13/48 53/33 17/49 55/34 263/262 44/39

Based on the same reference, the number of trips expected to be generated by a supermarket [ITE Code: 820] with 117,600 gross floor area on a 10-acre tract, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per
1,000 gfa
117.25* 2.01 10.34 11.06 12.39 177.59 15.33
%enter/%exit 50%/50% 70%/30% 51%/49% 49%/51% 53%/47% 50%/50% 51%/49%
Total Trips 13,789 236 1,216 1,301 1,457 20,885 1,803
Enter/Exit 6,895/6,894 165/71 620/596 637/663 772/685 10,443/10,442 919/8830
* no information available in reference; rate shown based on 10 times average of AM and PM Peak hour rates.

North 70.1 Acres

Based on the applicable reference in 1999, the Sixth Edition of the ITE TRIP GENERATION, the number of trips expected to be generated by a manufactured housing development [ITE Code: 240], consisting of 157 units in a 31.45-acre tract, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per unit 4.81 0.40 0.56 0.43 0.58 4.97 0.54
%enter/%exit 50%/50% 21%/79% 62%/38% 26%/74% 62%/38% 50%/50% 53%/47%
Total Trips 755 63 88 68 91 780 85
Enter/Exit 378/377 13/50 55/33 18/50 56/35 390/390 45/40

Based on the same reference, the number of trips expected to be generated by a shopping center [ITE Code: 820], with 389,906 square feet of gross leasable area in a 38.75-acre tract, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1,000 gla 42.92 1.03 3.74 - - 49.97 4.97
%enter/%exit 50%/50% 61%/39% 48%/52% - - 50%/50% 52%/48%
Total Trips 16,992 408 1,481 - - 19,783 1,968
Enter/Exit 8,496/8,496 249/159 711/770 - - 9,892/9,891 1,023/945
- no information available

The total number of trips to be generated by the development of the 100.7 acres proposed in January 1999, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Saturday
(24 hrs)
Saturday
Peak
Total Trips 32,272 768 2,871 41,973 3,939
Enter/Exit 16,136/16,136 440/328 1,439/1,432 20,987/20,986 2,031/1,907

WESTWOOD CENTER TRIP GENERATION

South "40.6" Acres - 31.139 Acres

The south 40.6 acres of the Stonebridge POADP, after the final determination of the 100-year flood plain of Culebra Creek, yields 31.139 acres of developable property along Culebra Road. The 31.139 acres include the initial 10.0 acres, initially proposed for a supermarket, and 21.139 acres of the 30.6 acres which were initially proposed for manufactured housing. The 10.0 acres are presently proposed to be developed with a fast-food restaurant with a drive-through window and a shopping center with a peripheral pad site. The remaining 21.139 acres are also proposed to be developed as a shopping center with peripheral pad sites. The peripheral pad sites may be restaurants, specialty retail stores, and/or gasoline/service stations with convenience markets. The development of the south "40.6" acres, would be as follows:

Lot 1, Unit 5: Fast food restaurant with drive-through window
Lot 2, Unit 5 and Lot 4, Unit 6: Shopping Center (Lot 4) with peripheral pad site (Lot 2)
Lot 3, Unit 5 and Lot 5, Unit 7: Shopping Center (Lot 5) with peripheral pad site (Lot 3)

Based on the ITE TRIP GENERATION, Sixth Edition, the number of trips expected to be generated by a fast food restaurant with a drive-through window [ITE Code: 834], with 1,230 square feet of gross floor are (a Sonic Drive In Restaurant) on proposed Lot 1, Unit 5 (0.918 acre), would be as follows:

Weekday
(24 hrs)
>Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1,000 gfa 496.12 49.86 33.48 54.81 46.28 722.03 58.91
%enter/%exit 50%/50% 51%/49% 52%/48% 51%/49% 52%/48% 50%/50% 51%/49%
Total Trips 610 61 41 67 57 888 72
Enter/Exit 305/305 31/30 21/20 34/33 30/27 444/444 37/35

Based on the same Sixth Edition reference, the number of trips expected to be generated by a shopping center [ITE Code: 820], with 109,423 square feet of gross leasable area (based on gross leasable area being 25% of lot area) on proposed Lot 2, Unit 5 and Lot 4, Unit 6 (10.048 acres), would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday Peak
Trips per 1,000 gla 42.92 1.03 3.74 - - 49.97 4.97
%enter/%exit 50%/50% 61%/39% 48%/52% - - 50%/50% 52%/48%
Total Trips 4,696 113 409 - - 5,468 544
Enter/Exit 2,348/2,348 69/44 196/213 - - 2,734/2,734 283/261
- no information available

Based on the same Sixth Edition reference, the number of trips expected to be generated by a shopping center [ITE Code: 820], with 219,684 square feet of gross leasable area on proposed Lot 3, Unit 5 and Lot 5, Unit 7 (20.173 acres), would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1000 gla 42.92 1.03 3.74 - - 49.97 4.97
%enter/%exit 50%/50% 1%/39% 48%/52% - - 50%/50% 52%/48%
Total Trips 16,992 408 1,481 - - 19,783 1,968
Enter/Exit 8,496/8,496 249/159 711/770 - - 9,892/9,891 1,023/945
- no information available

North "70.1" Acres - 68.017 Acres

The north 70.1 acres of the Stonebridge POADP, after the final determination of the 100-year floodplain of Culebra Creek, yields 68.017 acres of developable property along Leslie Road. The 68.017 acres consist of 32.341 acres proposed for multi-family development (up to 20 units per acre), a 24.458-acre Wal*Mart site with 204,000 square feet of gross floor area, a possible fast-food restaurant on a peripheral pad site to the Wal*Mart development, and a shopping center with detached building sites. The development of the north "70.1" acres, as shown on the attached Master Plan for the Westwood Center Subdivision, would be as follows:

Lot 1, Unit 8: Multi-family development (up to 647 units)
Lot 1, Unit 9: Fast Food Restaurant with drive thorough window (6,534 square feet, being 15% of 1.0 acre lot)
Unit 2: Wal*Mart site (24.458 acres)
Lot 1, Unit 4 and Unit 10: 111,274 square feet of gross leasable area, being 25% of 10.218 acres of shopping center with detached buildings

Based on the Sixth Edition of the ITE TRIP GENERATION, the number of trips expected to be generated by a multi-family (apartment) development [ITE Code: 200], consisting of 647 units in a 32.341-are tract, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per unit 6.63 0.51 0.62 0.56 0.67 6.39 0.52
%enter/%exit 50%/50% 16%/84% 67%/33% 28%/72% 61%/39% 50%/50% 50%/50%
Total Trips 4,290 330 401 362 433 4,134 336
Enter/Exit 2,145/2,145 53/277 269/132 101/261 264/169 2,067/2,067 168/168

Based on the Sixth Edition of the ITE TRIP GENERATION, the number of trips expected to be generated by a fast food restaurant with a drive-through window [ITE Code: 834], with up to 6,534 square feet of floor area (based on 15% of the lot area) on proposed Lot 1, Unit 9 (1.00 acre), would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1,000 gfa 496.12 49.86 33.48 54.81 46.28 722.03 58.91
%enter/%exit 50%/50% 51%/49% 52%/48% 51%/49% 52%/48% 50%/50% 51%/49%
Total Trips 3,242 326 160 358 302 4,718 385
Enter/Exit 1,621/1,621 166/160 83/77 183/175 157/145 2,359/2,359 196/189

Based on the Sixth Edition of the ITE TRIP GENERATION, the number of trips expected to be generated by the Wal*Mart Development (a free-standing discount store) [ITE Code: 815], with 204,000 square feet of gross floor area 24.458-acre lot, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1,000 gfa 56.63 0.99 4.24 5.82 5.51 72.03 7.66
%enter/%exit 50%/50% 66%/34% 50%/50% 50%/50% 50%/50% 50%/50% 51%/49%
Total Trips 11,553 202 865 1,187 1,124 14,694 1,563
Enter/Exit 5,777/5,776 133/69 433/432 594/593 562/562 7,347/7,347 797/766

Based on the Sixth Edition ITE TRIP GENERATION, the number of trips expected to be generated by a shopping center [ITE Code: 820], with 111,274 square feet of gross leasable area on the 10.218 acres which would include Lot 1, Unit 4 and the proposed Unit 10, would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6
Weekday
AM Peak
Weekday
PM Peak
Saturday
(24 hrs)
Saturday
Peak
Trips per 1000 gla 42.92 1.03 3.74 - - 49.97 4.97
%enter/%exit 50%/50% 61%/39% 48%/52% - - 50%/50% 52%/48%
Total Trips 4,776 115 416 - - 5,560 553
Enter/Exit 2,388/2,388 70/45 200/216 - - 2,780/2,780 288/265
- no information available

The total number of trips to be generated by the development of the proposed Westwood Center would be as follows:

Weekday
(24 hrs)
Weekday
7-9 AM
Weekday
4-6 PM
Saturday
(24 hrs)
Saturday
Peak
Total Trips 46,159 1,555 3,773 55,245 5,421
Enter/Exit 23,080/23,079 771/784 1,913/1,860 27,623/27,622 2,792/2,629

WESTWOOD CENTER TRIP DISTRIBUTION

The trips would be distributed to the drives serving the individual developments and to the Westwood Loop and Westwood Vista. Westwood Loop is proposed as an internal roadway crossing Culebra Creek designed to serve the developments within Westwood Center. Westwood Vista is proposed as an internal roadway, connecting Leslie Road and Westwood Loop. Due to the proposed configuration of the Loop 1604 southbound exit ramp to the Culebra Road/1604 interchange, no significant through traffic is anticipated to utilize Westwood Loop or Westwood Vista as a connection between Loop 1604 and Culebra Road.

The Westwood Center would be divided into five general areas, each area having internal circulation to allow trips to be distributed to any of the drives around each area. For the purpose of this report, cross-trips between areas are not being considered, thus providing the maximum anticipated load on the roadway system. The five areas are

  • Area 6, which would include proposed Lots 1 and 2, Unit 5 and Lot 4, Unit 6
  • Area 7, which would include proposed Lot 3, Unit 5 and Lot 5, Unit 7
  • Area 8, which would consist of Lot 1, Unit 8
  • Area 9, which would include the Wal*Mart development and proposed Lot 1, Unit 9
  • Area 10, which would include Lot 1, Unit 4, and the 8.978 acres of Unit 10.

Area 6 would be expected to be served by a one-way couplet of drives onto Culebra Road for Lot 1 (the Sonic Drive-In site), by one (1) two-way drive onto Culebra Road and one (1) two-way drive onto Westwood Loop for the corner Lot 2, and by as many as three (3) two-way drives onto Culebra Road and two (2) two-way drives onto Westwood Loop for Lot 4. Lot 4 would have approximately 470 feet of frontage along Culebra Road and approximately 425 linear feet of frontage along Westwood Loop.

Area 7 would be expected to be served by one (1) two-way drive onto Culebra Road and one (1) two-way drive onto Westwood Loop for the corner Lot 3 and as many as five (5) two-way drives onto Culebra Road and by two (2) two-way drives onto Westwood Loop for Lot 5. Lot 5 would have approximately 1,065 linear feet of frontage along Culebra Road and 420 linear feet of frontage along Westwood Loop.

Area 8, which is proposed for multi-family development with approximately 300 feet of frontage along Westwood Loop, would be expected to be served by two (2) two-way drives onto Westwood Loop.

Area 9 would be expected to be served by one (1) two-way drive onto Leslie Road and two (2) two-way drives onto Westwood Loop for the corner Lot 1 and by two (2) two-way drives onto Leslie Road and three (3) two-way drives onto Westwood Loop for the Wal*Mart lot. The Wal*Mart lot has approximately 875 feet of frontage along Leslie Road and approximately 550 linear feet of frontage along Westwood Loop.

Area 10 would have limited access due to the proximity of the southbound exit ramp from Loop 1604 onto Leslie Road. The corner Lot 1 would be expected to be served by a one-way entrance drive from Leslie Road and two-way drive onto Westwood Vista. The remainder of the area would be expected to be served by one (1) two-way (or a one-way couplet) drive onto Leslie Road, as many as three (3) drives o Westwood Vista, and as many as four (4) drives onto Westwood Loop. The 8.978 acres would have approximately 790 feet of frontage along Westwood Vista and approximately 800 feet of frontage along Westwood Loop.

Assuming that the area west of the Westwood Center continues to develop and that FM 1560 continues to serve as a north-south route for accessing Culebra Road, a general equal split between right turns and left turns on Culebra Road would be expected. All turning movements onto and from Leslie Road would be limited to right turns. The turning movements onto and from Westwood Loop and Westwood Vista are assumed to be equally split between right and left turns for this distribution.

The peak hour distribution of trips (assuming one vehicle per trip) for each area would be as follows. The peak hours enumerated would be those times when the adjacent roadways would have peak traffic flows: Weekday 7-9 AM and Weekday 4-6 PM. The Saturday peak hour distribution is also enumerated.

AREA 6
Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Lot 1 - Culebra Road* 15 16 15 15 10 11 10 10 18 19 17 18
Lot 4 E - Culebra Road 4 5 4 3 14 14 16 15 21 20 19 19
Lot 4 M - Culebra Road 5 5 4 3 14 14 16 15 21 20 19 19
Lot 4 W - Culebra Road 5 5 3 3 14 14 16 15 21 20 19 18
Lot 2 - Culebra Road 5 5 3 3 14 14 15 15 20 20 19 18
Lot 2 - Westwood Loop 5 5 3 3 14 14 15 15 20 20 19 18
Lot 4 S - Westwood Loop 5 5 3 3 14 14 15 15 20 20 19 18
Lot 4 N - Westwood Loop 5 5 3 3 14 14 15 15 20 20 19 18
* one-way couplet
AREA 7
Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Lot 3 - Culebra Road 14 14 9 9 39 40 43 43 57 57 52 53
Lot 7 E - Culebra Road 14 14 9 9 39 40 43 43 57 57 52 53
Lot 7 EM - Culebra Road 14 14 9 9 39 40 43 43 57 57 52 53
Lot 7 M - Culebra Road 14 14 9 9 39 40 43 43 57 57 52 53
Lot 7 WM - Culebra Road 14 14 9 9 39 40 43 43 57 57 52 53
Lot 7 W - Culebra Road 14 14 9 9 39 40 42 43 57 57 52 53
Lot 3 - Westwood Loop 14 13 9 8 39 40 42 43 57 56 52 53
Lot 7 S - Westwood Loop 14 13 9 8 39 40 42 43 57 56 52 53
Lot 7 N - Westwood Loop 14 13 9 8 39 40 42 43 57 56 52 53
AREA 8
Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Lot 1 N - Westwood Loop 13 13 69 69 67 67 33 33 49 49 47 47
Lot 1 S - Westwood Loop 14 13 69 70 68 67 33 33 49 49 47 48
AREA 9
Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Lot 1 - Leslie Road - 56 - 54 - 27 - 25 - 66 - 63
Wal*Mart S - Leslie Road - 26 - 13 - 86 - 87 - 160 - 154
Wal*Mart N - Leslie Road - 26 - 14 - 86 - 87 - 160 - 153
Lot 1 E - Westwood Loop 28 27 27 26 14 14 13 13 33 32 32 31
Lot 1 W - Westwood Loop 28 27 27 26 14 14 13 13 33 32 32 31
Wal*Mart E - Westwood Loop 13 14 7 7 43 44 43 43 79 80 76 77
Wal*Mart M - Westwood Loop 13 14 7 7 43 44 43 43 79 80 76 77
Wal*Mart W - Westwood Loop 13 14 7 7 43 44 43 43 79 80 76 77
AREA 10
Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Lot 1 - Leslie Road ** - 7 - - - 10 - - - 29 - -
8.978 Acres - Leslie Road - 7 - 5 - 10 - 24 - 29 - 30
Lot 1 - Westwood Vista 3 4 3 2 5 5 12 12 28 29 14 15
8.978 Acres E - Westwood Vista 3 4 3 2 5 5 12 12 28 29 14 15
8.978 Acres M - Westwood Vista 3 4 3 2 5 5 12 12 29 29 14 15
8.978 Acres W - Westwood Vista 3 4 3 2 5 5 12 12 29 29 14 15
8.978 Acres W - Westwood Loop 3 4 3 2 5 5 12 12 29 29 14 15
8.978 Acres MW - Westwood Loop 3 4 3 2 5 5 12 12 29 29 15 15
8.978 Acres ME - Westwood Loop 3 4 3 2 5 5 12 12 29 29 15 15
8.978 Acres E. - Westwood Loop 3 4 3 2 5 5 12 12 29 29 15 15
**entrance only

The anticipated peak hour trip distribution at Westwood Loop at Culebra Road, Westwood Loop at Leslie Road, and Westwood Vista at Leslie Road would be as follows, based on teh above area trip distributions:

Driveway Weekday 7-9 AM Weekday 4-6 PM Saturday Peak
Enter Exit Enter Exit Enter Exit
left right left right left right left right left right left right
Westwood Loop @ Culebra Road 103 103 132 133 245 246 245 246 426 427 361 362
Westwood Loop @ Leslie Road - 134 - 221 - 315 - 269 - 518 - 446
Westwood Vista @ Leslie Road - 71 - 48 - 182 - 219 - 343 - 266

CONCLUSION

The proposed driveways should be adequate to accommodate the trip distribution from each area. Each area would have internal traffic circulation to allow the patron the choice of any of the drives serving the area to access all portions of the area. The resulting vehicle load at the intersections of Westwood Loop and Westwood Vista with Leslie Road should be adequately handled by the one-way operation of Leslie Road which would restrict the vehicle maneuvers to right turns only. The intersection of Westwood Loop and Culebra Road would be subjected to significant vehicle approach volumes during the Saturday peak period when Westwood Center is fully developed.

With exception to the Wal*Mart development, which represents nearly 1/4 of the developable area, the development of the remainder of the Westwood Center is anticipated to be over at least a ten-year period. During that time, Culebra Road (FM 471) is proposed to be improved to at least a four-lane facility with a continuous two-way left turn lane between Loop 1604 and FM 1560. In addition, Loop 1604 is proposed to be improved to a full freeway section during that time period, with a main-lane overpass at Culebra Road.

Culebra Road is projected to be improved as a seven-lane facility west of Loop 1604, when improved to its ultimate design width. In the interim, the more immediate Culebra Road improvements might include provisions for an additional westbound lane from Loop 1604 to the west boundary of the Westwood Center to separate the slower moving right turn traffic from the two westbound through lanes of Culebra Road. In addition, provisions should be included in the Culebra Road improvements to install a traffic signal at the intersection of Westwood Loop and Culebra Road, by providing conduit and loop detectors under the Culebra Road pavement.

Prepared by: Joe F. Nix, P.E.