Item 8 - TIA Statec response to LeeStantec
January 29, 2016
File: 198110064
Attention: Jimmy Fechter, RLA
Adams I Engineering & Development Consultants
910 S. Kimball Avenue
Southlake, Texas 76092
Dear Mr. Fechter,
Reference: Responses to Lee Engineering Comments for Pinnacle Point TIA
This letter contains responses to the comments about the Pinnacle Point TIA, submitted January 19,
2016. Lee Engineering has reviewed the study, and submitted comments on January 28, 2016. For
each of the "action comments" (which require a response or action by city or applicant) made,
our response is given below (Note that time was not available to make updates to hard copies of
the TIA submitted earlier today):
1-3: These were informational comments, which did not require action.
4: The TIA states that the extension of South Village Center Drive east of Kimball Avenue has an estimated
implementation date at least 7 years in the future (page 1.2), which would be 2022. However, site traffic was
assumed to have access to South Village Center Drive at site build -out in 2018.
The TIA should not include traffic assignments to Village Center Drive or Village Center Court for
the 2018 buildout analysis unless those roadways will be in place by then.
The developer's intent at the time the TIA was scoped was to evaluate an ideal scenario
where all buildings could be constructed to meet presumed market demand by 2018 and
thus illustrate to the City the utility of having the new roadways in place. If no funding is
available for roadway construction until 2022 or later, the developer is committed to delay
Phase 2 until such time as the new roads will be in place.
5: No 2018 background analysis is provided for the Kimball driveway intersection.
We did not scope 2018 background analysis at the Kimball driveway intersection since little
if any meaningful information would come from it. It would be similar to the existing
condition where no side street traffic is approaching. The school would continue to be
one-way in, there'd be no driveway on the east side, and so no delay would occur for
anyone except small delay for northbound left turns into the school.
The TIA says the assumed background retail development northwest of site includes 23,000 ftz remaining
(page 3.2), but the trip generation spreadsheet in Appendix C uses 20,000 ft2.
Design with community in mind
January 29, 2016
Jimmy Fechter, RLA
Page 2 of 4
Reference: Error! Reference source not found.
The trip generation worksheet in Appendix C had 23,000 square feet entered, but the
value in the spreadsheet was displayed as rounded. This was fixed in the worksheet to be
used for any future submissions to show 23,000 square feet. Since the correct value had
been used in the analysis, no further revisions to the study would be needed.
The AM peak hour capacity analysis utilized peak hour factors of 0.92 to 1.0. This peak hour factor will not
account for the peak flow characteristics of the school driveway that shares the median opening with the
proposed development driveway. The analysis should be revised to use peak hour factors that consider school
traffic operations.
The peak hour factors along Kimball Avenue were not carried over from the previous
submission to the revised Pinnacle Point TIA. After entering the correct peak hours, the
Synchro analysis was rerun for both phases. In Phase 1, the worst movement delay at the
study intersection increases from 40 seconds to 44 seconds for the AM westbound left turn
from the site driveway. The result remains LOS E, and none of the other movements have
worse LOS after the correction. In Phase 2, the westbound left turn out of the site driveway
onto Kimball Avenue had a delay increase of around 20-30 seconds for each peak hour;
however, this movement was already operating at LOS F. Otherwise, delay and queues
remained nearly identical, and the conclusions of the study would not need revision.
8: There is a roundabout/oval intersection within the site. Autoturn exhibits for a SU 40 and WB 50 design vehicle
were provided. No Autoturn exhibit for a Southlake fire department vehicle was provided.
The internal intersection should be revised to better accommodate the various design vehicles
anticipated for the site.
The layout should be reviewed by the Fire Department to determine if it is acceptable.
Comment noted. Consultant to coordinate with City staff.
9: Table 7 in the TIA addresses Intersection Sight Distance. However, it is unclear where the recommended
stopping sight distance in the table is coming from as it does not match AASHTO Intersection Sight Distance
or Stopping Sight Distance for the posted 35 mph or stated 40 mph design speed.
The stopping sight distance for a 40 mph design speed is 305 feet.
Intersection sight distance for a 40 mph design speed for the left turn from the minor roadway,
case B1, with an 8.0 second time gap due to the 4 lane divided roadway is 475 feet.
Stopping sight distances had been adjusted for a 3% grade in previous versions of the
report. We agree that intersection sight distance is more appropriate and that stopping
sight distance was included in the previous reports in error.
For left turns from a minor roadway, case B1, a time gap of 8.5 seconds
(considering the median as an "additional lane" to cross), and design speed of
Design with community in mind
January 29, 2016
Jimmy Fechter, RLA
Page 3 of 4
Reference: Error! Reference source not found.
40mph, recommended intersection sight distance is 500 feet, which will be
provided only if the existing median street trees are removed or replaced with trees
having a higher canopy as noted.
For right turns from a minor roadway, case 132, a time gap of 6.5 seconds (grade is
3% or less), and design speed of 40mph, recommended intersection sight distance
is 385 feet. The 470 feet of available sight distance is still sufficient compared to the
corrected, higher recommended threshold.
10: The TIA indicated that if left turn egress from the northern driveway is allowed, then the median landscaping
north of the site will require modification. We concur with this recommendation. The bottom of the tree canopy
should be at least T above the curb elevation Additionally, no shrubs or bushes should be taller than 24"
above the lower roadway elevation.
No action is needed for the TIA since this comment agrees with Stantec's
recommendation.
1 1 : Retaining wall is shown on the site plan with height etc. TBD. Intersection sight triangles will need to be
provided as the retaining wall plans are developed such that the retaining wall structures do not impede driver
visibility.
Comment noted. Consultant to coordinate with City staff.
12: No cross access is shown to adjoining properties. Cross access is generally desirable. Cross access to the
south should be considered so that future access to a second median opening could be obtained if the site to
the south redevelops.
Comment noted. Consultant to coordinate with City staff.
13: The driveways to Village Center Court have throat depths that do not satisfy the driveway ordinance. They will
require variances. Based on the information in the TIA the lengths shown in the site plan should operate
satisfactorily. Kimball does not have a sufficient throat depth.
If buildout of the site occurs before Village Center Drive and Village Center Court are constructed
then the driveway to Kimball does not have a sufficient throat depth since 450 parking spaces
would be served by a single driveway. This is an issue more about timing than throat depth as
the 100' throat depth shown in the site plan is sufficient once the Village Center Drive and the
Village Center Court roadways are in place.
The 100' throat depth would be appropriate if buildout occurs prior to the adjoining roadways if
the secondary access on Kimball is provided.
Variances will not be required since the developer does not intend for full build -out prior to
construction of the new roadways. See response to Comment #4 above.
Design with community in mind
January 29, 2016
Jimmy Fechter, RLA
Page 4 of 4
Reference: Error! Reference source not found.
14: There do appear to be any sidewalk connections shown from Kimball Avenue or Village Center Court into the
site.
Comment noted. Consultant to coordinate with City staff.
If you have any questions, please feel free to contact me at 214-468-8200 - Ext. 1104.
Sincerely
Josh Smith, P.E., PTOE
Project Manager
Phone: 214-468-8200 Ext. 1 104
Fax: 214-468-8266
Josh.Smith@stantec.com
Design with community in mind