Item 6C - Traffic Review Letter7 3030 LBJ FREEWAY
SUITE 1660
WALLAS, TX 75234
972-248-3006
www.LeeEngineering.com
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February 26, 2014
Miss Alex Ayala
City of Southlake
1400 Main Street, Suite 320
Southlake, Texas 76092
Re: Remington Estates Traffic Impact Review
Dear Miss Ayala:
Per your request, we have reviewed the trip generation letters related to the proposed Remington Estates
development along Shady Lane in Southlake. The trip generation letters were prepared by Binkley &
Barfield !C&P and dated on December 2, 2013 and January 29, 2014. The development plan provided
included a site plan with 23 proposed single family residential lots.
Our review comments are numbered for ease of reference and the numbering does not imply any ranking.
We have divided our comments into two categories — Informational Comments are those that require no
action by the city or the applicant. Action Comments are those that require a response or action by the
City or applicant. We offer the following comments on the submitted traffic impact analysis.
INFORMATIONAL COMMENTS (REQUIRE NO ACTION BY CITY OR APPLICANT)
The trip generation estimates prepared by the applicant utilized the Institute of Transportation
Engineers (ITE) Trip Generation average rates for the daily, AM peak, and PM peak hour trip
generation. In Trip Generation, ITE provides regression equations for some land uses, including
for land use 210: Single Family Detached Housing. Typically the regression equations should be
used, unless the development falls outside the typical sample size of the data set. A comparison
of the trip generation provided by the developer versus trip generation using the regression
equations are provided in the table below.
Table 1: Difference between Average Rate and Regression Equation Usage
Method
Dwelling
Daily Total
AM
AM
AM
PM
PM
PM
Units
Trips
Entering
Exiting
Total
Entering
Exiting
Total
Average
23
219
4
13
17
14
9
23
Rates
Regression
23
272
7
19
26
18
10
28
Equations
Difference
-
+53
+3
+6
+9
+4
+1
+5
t�
OF EX CAR S I E
As can be seen, use of the regression equation results in higher predicted trip numbers and may
represent a more conservative impact assessment. The average sample size in the ITE data set is
194 to 207 dwelling units for the three time periods studied. Because the Remington Estates
development is significantly smaller than the average development in Trip Generation, the
regression equation may overestimate the number of trips for smaller scale developments.
Use of the average rates as presented by the developer is acceptable in this instance, is within
industry norms, and the study does not require revision.
The total number of trips predicted to be generated by the development on both a daily basis and
during the PM Peak hour are far below the City of Southlake established thresholds for requiring
a TIA. A full TIA is not necessary for this development nor would it show any significant impacts
created by the development.
The trip generation letter from January 29, 2014 compares the differences in trips generated by
13 lots allowed under existing zoning with the 23 lots proposed for the development. Table 2
below illustrates the differences in the existing zoning and proposed zoning trip generation if the
regression equations are used.
Table 2: Difference between Existing Zoning and Proposed Zoning using regression equations
Method
Dwelling
Daily
Total
AM
AM
AM
PM
PM
PM
Units
Trips
Entering
Exiting
Total
Entering
Exiting
Total
Regression
Equations
13
161
5
14
19
11
6
17
(Existing
Zoning)
Regression
Equations
23
272
7
19
26
18
10
28
(Proposed
Zoning)
Difference
+10 D.U.
+111
+2
+5
+7
+7
+4
+11
4. There is undeveloped land adjacent to the proposed development that may in the future develop
as single family residential housing. The exact number of lots or timeframe for development is
completely unknown at this time. However, for the purposes of this traffic review, Lee
Engineering has estimated that 8 additional lots would be developed on the remaining property
adjacent to the proposed development. The trip generation range for the total of 31 lots is shown
in Table 3 below with both average rates and regression equation trip generation presented.
2
5�
YEARS
of EXC MINCE
Table 3: Estimated range of trip generation ultimate build out
Method
Dwelling Units
Daily
Total
AM
AM
AM
PM
PM
PM
Trips
Entering
Exiting
Total
Entering
Exiting
Total
Average
31
295
6
17
23
20
11
31
Rate
(23 + 8 future)
Regression
31
Equations
(23 f 8 future)
358
8
23
31
23
14
37
The developer made an assumption that all outbound trips would access the SH 114 frontage
road. Additionally, the developer estimated that less than 20%of inbound traffic would use Shady
Lane to access the Remington Estates. After reviewing approach and departure paths in the area,
we think it is likely that a somewhat higher percentage of both entering and exiting traffic is likely
to access the development via Shady Lane to or from the north.
o For traffic entering Remington Estates, traffic approaching from the west, north, and
south may all find access to Remington Estates to be more convenient from Shady Lane
to the north than from the westbound SH 114 frontage road depending on the time of
day and prevailing traffic conditions at the time.
o For traffic exiting Remington Estates, traffic exiting to the north and to some destinations
to the west may find Shady Lane a more convenient exit route than SH 114.
o The distribution of traffic into and out of Remington Estates will vary based on individual
motorists preferences, and will vary based on time of day and prevailing traffic conditions
at the time.
o Turning movement counts could be performed to determine existing directional splits
along Shady Lane at Kimball versus SH 114, however, even if these splits were applied to
Remington Estates estimated trip generation, no significant effects on capacity or delay
would be predicted.
o No revision to the study is necessary to account for the differing opinions on approach
and departure paths due to the overall low peak hour volumes being projected.
Ultimately the AM and PM peak hour volumes of traffic predicted to be generated by Remington
Estates are so low, that the increase in traffic from the new development should be hard to
perceive along Shady Lane. The volumes are low enough to almost blend into daily variations of
traffic.
o The absolute worst case from a resident's perspective would be a PM Peak hour where
all build out traffic traveled through the Shady Lane at Kimball intersection. Under this
scenario, only 23 cars would be entering the new development (at build out) and only 14
would be exiting the development (at build out).
o A majority of outbound traffic will use the Shady lane at SH 114 intersection and at least
25-50% of inbound traffic would be expected to use the SH 114 intersection as well. The
proposed development, along with additional future development of 8 lots, would be
expected to generate no more than 21 total PM peak hour trips on Shady Lane north of
Remington Estates.
3
YEARS
OF EXCELLENCE
ACTION COMMENTS (REQUIRE RESPONSE OR ACTION BY CITY OR APPLICANT)
7. Construction traffic for the development should be restricted to the segment of Shady lane
between SH 114 and the proposed Remington Estates roadway.
If you have any questions, please contact me at (972) 248-3006. We appreciate the opportunity to provide
these services and are available to address any additional comments or concerns.
Sincerely,
Irk L24-� rT
John P. Denholm III, P.E., PTOE
Sr. Project Engineer
Lee Engineering
TBPE Firm F-450
4
Y E A R S
Of ER¢EII M E