HomeMy WebLinkAboutTIAKimley-Hom
M and Associates, Inc.
MEMORANDUM
To: Matt Robinson, AICP
Joe Guerra, AICP, PTP
City of College Station
CC: Chuck Carroll
American Campus Communities
From: Jeff Whitacre, P.E.
Adam Gibson, P.E.
Kimley-Horn and Associates, Inc.
Date: March 25, 2011
Subject: Luther Street Student Housing (Sp) — Site Plan
Response to March 16, 2011 City Comments
In response to the review letter dated March 16, 2011, regarding the Callaway
Subdivision Traffic Impact Analysis (TIA), we offer the following responses.
We have formatted this response in a manner where the City's comments appear
in italics prior to Kimley-HorWs response. This memo is intended to serve as a
supplement to the Callaway Subdivision TIA - December 2010.
1. General Comments
a) Because 30% transit trip reduction will be used and is a significant
reduction, justification documentation must beprovided- the word
of the applicant is not reasonable documentation
Transportation Services at Texas A&M University was contacted to
see if records were available to use as an assumption for a transit
reduction. No information was available. Based on feedback from
the operator of an existing neighboring development (Callaway
Villas), the ridership was estimated to be roughly 30% of the
residents at the beginning of the semester. It was estimated to
increase as high as to 50% as the semester progresses. Looking at
the raw numbers, the PM peak would be expected to have 38
students using transit (or non -auto) arriving to the complex. Given
the frequency of the buses this appears a reasonable assumption
The 30% was further explored by analyzing the 2000 census for the
77840 zip code. The census showed only 71.4% drove alone to
work. Using this as a guide, the 30% appeared reasonable given the
proximity of the student housing to the TAMU campus.
Callaway Subdivision Traffic Impact Analysis
College Station
March 2011
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Kimley-Hom
and Associates, Inc.
Subject Number Percent
EMPLOYMENTSTATUS
Population 16 years and over
42,778
100.0%
In labor force
25,081
58.6%
COMMUTING TO WORK
Workers 16 years and over
20,019
100.0%
Car, truck, or van - drove alone 14,285 71.4%
Source: U.S. Census Bureau, Census 2000
Compiled by the North Central Texas Council of Governments
To compare the reasonability of this reduction an adjacent
apartment complex vehicular trips were counted during the PM
peak period. The vehicular trip generation rate was 0.29 trips per
person as opposed to the 0.40 trips per person identified in ITE Trip
Generation. This 27.5% reduction was attributed to non -vehicular
trips and verified that the 30% reduction was reasonable.
b) The statement in the TIA, "Per the City of College Station's Unified
Development Ordinance (UDO), mitigation ofdeficiencies is
required by the Applicant ifproject traffic contributes at least S
percent (S%) of the peak hour traffic " is misinterpreted This is only
applicable if traffic is alreadyfalling to meet Level of Service "LOS
D ". The minimum LOS standard is LOS D. The following is the
language in the UDO; "Where the development is contributing five
percent (S%) or more of the traffic at locations failing to meet LOS
D or better the total trips should be mitigated by the applicant to
low enough levels to achieve the required standard (or to pre -
development levels, whichever is greater).
The UDC states: "A description of the mitigation measures proposed
for achieving acceptable service thresholds shall be shown. Analysis of
the study network as adjusted by the proposed measures must be
documented. Traffic produced by the proposed zoning request plus
traffic levels projected by the time of project occupancy should result in
Level of Service D or better. Locations not meeting Level of Service D
where the proposed zoning contributes five percent (5%) or more of the
peak hour traffic must be mitigated by the applicant. Acceptable
methods of mitigating negative traffic impacts include any one, or a
combination of, the measures listed below but is not limited to those
listed."
Based on recent discussion with the City it has been determined that the
interpretation in the TIA is correct. The interpretation is if a location's
level of service is less than D and the site contributes 5% or more of the
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Kimley-Hom
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peak hour traffic, then mitigation recommendations will be required by
the applicant.
c) Yes, the City agrees the applicant can use the extension of Jones
Butler as an existing facility
The TIA concurs that the Jones Butler extension is an important
connection in this area.
d) No, the assumption that the RDOT improvements on George Bush
and Wellborn are imminent can be made. There are presently no
construction funds only engineering design funds
Noted. The TxDOT improvement at the George Bush & Wellborn
intersection was not included in the analysis. It was mentioned the TxDOT
has planned improvements which will ultimately improve this intersection.
2. Specific Comments
a) Table 1-Trip Generation illustrates, III net trips inbound for the
pm peak hour yet in Figure 7 the only inbound opportunity is thru
the northernmost driveway and it illustrates 61 trips inbound in the
pm peak. This brings into question how the trip distribution was
conceptualized.
The site is projected to service 111 net trips inbound during the PM peak.
Figure 7 illustrates this. The 61 trips previously mentioned are the
northbound right -turn trips into the site, but an additional 50 trips are shown
on the southbound left. The resulting 61+50 trips = I I I net hips.
b) According to the UDO Article 7, Section 7.3, subsection 7
paragraph L, a deceleration lane may be required for an access
with projected peak hour right turn ingress of 50 vehicles per hour
(vph). The Cityfeels the deceleration lane is warranted at the
northernmost driveway especially since this is the only ingress into
the sight
The ultimate site traffic (Figure 10) shows an ultimate northbound right -
turn volume of 50 vehicles. According to the UDC this is the minimal
volume when considering a right -tun deceleration lane. With a projected
volume of 219 vehicles traveling northbound on Marion Pugh during the
PM peak, the facility is projected to operate at a high level of service. The
vehicles traveling northbound on Marion Pugh are traveling at a lower speed
and the impact of the right -turning vehicles are projected to be minimal. In
addition, an existing bike lane is on Marion Pugh between Holleman Drive
and Luther Sheet. The introduction of a right -turn lane at a minor drive on
an existing designated bicycle facility is not recommended. Using the
charts on page 23 (Figure 2-6 Guideline for determing the need for a major -
Callaway Subdivision Traffic Impact Analysis March 2011
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Kimley-Horn
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road right -turn bay at a two way stop -controlled intersection) of NCHRP
457 a right -turn bay would not be recommended per this guideline.
c) At Holleman and Marion Pugh the southbound left turn movement
fails LOSE and there is a S % increase in traffic thru the
intersection. Westbound movements are not shown in Table 4.
Mitigation is required for southbound left turn movements. Options
to include warrant study for signalization or a duel left
configuration.
The intersection of Holleman & Marion Pugh is a t-intersection with the
southbound approach being stop -controlled. The westbound approach has
right-of-way and by definition has no delay associated with it, so it was left
off of Table 4. The southbound approach currently has a dedicated left -turn
lane and a dedicated right -turn lane. Dual left -turn lanes at unsignalized
intersections are very rarely used except as a last resort, due to the difficulty
of gap selection and the lack of positive driver guidance into the receiving
lanes. Turning southbound dual lefts from Marion Pugh onto Holleman
may be difficult due to receiving lane capacity on Holleman.
Unsignalized intersection's level of service should be closely examined on a
case -by -case basis to account for the external factors that may affect the
level of service at the intersection. The HCM methodology was originally
developed for low to moderate volume locations where traffic is evenly
distributed. For unsignalized intersections located on major thoroughfares
the traffic may not be evenly distributed. As a result, the methodology may
be deficient and overestimate actual experienced level of service. The 44.5
seconds delay associated with the southbound left -turn from Marion Pugh
on to Holleman would be equal to level of service D if the approach was
considered signalized. The project 95`h percentile queue length for the
southbound approach is approximately six (6) vehicles. Likely, the delay is
contributed to waiting for a usable gap, not from the overwhelming number
of vehicles making the turn.
The projected volumes at this intersection is projected to not satisfy any of
the signal warrants listed in the Manual on Uniform Traffic Control Devices
(MUTCD), so this mitigation solution does not meet minimum standards for
signalization. The intersection should be monitored as a candidate for
future signalization if traffic patterns significantly increase from what is
projected in the TIA.
The installation of an all -way stop would mitigate the southbound approach,
but would also have a significant negative effect on the more heavily -
travelled east- and westbound approaches. The table below illustrates the
LOS with the various potential mitigations.
Callaway Subdivision Traffic Impact Analysis March 2011
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Kimley-Hom
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Table — Mitigation at Marion Pugh & Holleman — Future Network
Intersection
AM Peak Hour
PM Peak Hour
Delay'
LOS
Delay
LOS
Marion Pugh &
Holleman
Existing Configuration
-From Report
SBLT
14.4
B
44.5
E
SBRT
10.3
B
11.2
B
EB
2.1
A
1.8
A
WB
0.0
A
0.0
A
OVERALL
2.2
A
9.1
A
Marion Pugh &
Holleman
-Signalized
SBLT
8.6
A
11.9
B
SBRT
8.1
A
10.1
B
EB
6.0
A
7.9
A
WB
7.0
A
9.1
A
OVERALL
6.9
A
9.2
A
Marion Pugh &
Holleman
-All-Way Stop
SBLT
9.2
A
14.6
B
SBRT
7.2
A
8.9
A
EB
9.1
A
17.1
C
WB
10.8
A
24.0
C
OVERALL
10.1
B
19.2
C
Delay is reported as HCM delay in see / veh
Based on the above information we do not believe that the southbound left -
turn movement would result in an unacceptable operating condition with the
existing two-way stop control and lane configuration. We recommend the
City and developer monitor the operations at this intersection and install an
all -way stop or a signal only if necessary and if the intersection meets the
appropriate traffic volume thresholds. Although the installation of an all -
way stop would mitigate the southbound approach, it may not be the optimal
solution for the roadway network.
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Nrrdey-Hom
and Asmdales, Inc.
d) At the George Bush and Wellborn Intersection, the turning
movements, northbound left, northbound east through, and
southbound west left were all failing (pm peak hour) with regards to
LOS and continued to fail in the pm peak hour future network
scenario with traffic increasing by 5% This intersection will have
to be mitigated at those turning movement locations
The intersection of George Bush & Wellborn has poor existing level of
service. The development has minimal impact on this intersection. In both
the AM and PM peaks, the volumes from the development through the
intersection are less than 2% of the total traffic and no mitigation
recommendations by the development should be required.
Should you have any questions or comments, please do not hesitate to call me at
(817)335-6511.
Sincerely,
KIMLEY-HORN AND ASSOCIATES, INC.
Jeff Whitacre, P.E.
Callaway Subdivision Traffic hnpact Analysis March 2011
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