Item 6C TIAA TRAFFIC IMPACT ANALYSIS FOR
A PROPOSED MIXED -USE DEVELOPMENT
IN SOUTHLAKE, TEXAS
Prepared for:
Canterra Development Group
Carpe Diem Academy
222 Municipal Drive, Suite 150
Richardson, TX 75080
Prepared by:
DeShazo, Tang & Associates, Inc.
DT &A #09203
Engineers • Planners
TEXAS REGISTERED ENGINEERING FIRM F -3199
400 South Houston Street
Suite 330 • Union Station
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Dallas, Texas 75202
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Phone: 214 - 748 -6740
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Fax: 214 - 748 -7037
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December 29, 2009
DT &A #09203
DeShazo, Tang & Associates, Inc.
Engineers + Planners
400 S. Houston St., Suite 330
Dallas, Texas 75202
(214) 748 -6740
FAX (214) 748 -7037
www.deshazotang.com
Technical Memorandum
To: Canterra Development Group
From: DeShazo, Tang & Associates, Inc.
Date: December 29, 2009
Subject: Traffic Impact Study Update for a Mixed -Use Commercial Development in Southlake,
Texas; DT &A #09203
INTRODUCTION
Canterra Development Group has retained DeShazo, Tang & Associates, Inc. (DTA) to update the
December 2005 traffic impact study for a mixed -use development located in the northwest
quadrant of the FM 1709 (Southlake Boulevard) /FM 1938 (Randol Mill Road) intersection in the
city of Southlake, Texas. This update is precipitated by a change in the overall development
scheme to replace several small office buildings with a daycare facility. This report summarizes
the results of the impact analysis associated with the latest building plan. The proposed site and
study area are shown in Exhibit 1.
COMPARISON OF PREVIOUS AND PROPOSED BUILDING PLANS
The previous traffic impact study was submitted on December 20, 2005. It was prepared for a
proposed development plan that included general office, shopping center, supermarket, bank and
fast food land uses. The 2009 building plan converts the general office (the only land use not
already constructed) to a daycare facility with a maximum attendance of 200 students. Table 1
illustrates both the 2005 and 2009 building plans.
Table 1— Building Plan Comparison
ITE
Code
ITE
Land Use
Quantity
2005 Plan
2009 Plan
565
Daycare
N/A
15,000 ±SF / 200 students
813
General Office
27,354 SF
N/A
820
Retail Shopping Center
12,505 SF
12,205 SF
850
Supermarket
27,605 SF
27,605 SF
912
Drive -In Bank
3,829 SF
3,829 SF
934
Fast -Food Restaurant w/ Drive Thru
2,154 SF
2,154 SF
Totals:
73,447 SF
61,093 SF
Mixed -Use Development TIA
Page 2
DeShazo, Tang & Associates, Inc.
December 29, 2009
COMPARISON OF PREVIOUS AND PROPOSED TRIP GENERATION
A trip generation summary from the 2005 study at site buildout is provided in Table 2. A trip
generation summary using the 2009 building plan is shown in Table 3. Comparing these two
tables, we find that the overall trip generation increases by 85 trips (25 %) during the AM peak
hour and 29 trips (3.4 %) during the PM peak hour. These increases will be the focus of the
remainder of this update.
Table 2 — 2005 Trip Generation
ITE
Code
ITE
Land Use
Quantity
AM Peak Hour
PM Peak Hour
Total
In
Out
Total
In
Out
710
General Office
27,354 SF
66
58
8
109
19
90
820
Retail Shopping Center
12,505 SF
45
27
18
159
76
83
850
Supermarket
27,605 SF
68
41
27
337
172
165
912
Drive -In Bank
3,829 SF
1 47
1 26
1 21
1 175
88
1 87
934
Fast -Food Restaurant w/ Drive Thru
2,154 SF
114
58
56
75
39
36
Totals:
1 340
210
130
1 855
394
461
Table 3 — 2009 Trip Generation
ITE
Code
ITE
Land Use
Quantity
Peak Hour
PM Peak Hour
T
In
Out
Total
In
Out
565
Daycare (adjacent Street)
200 Students
151
80
71
138
65
73
820
Retail Shopping Center
12,505 SF
45
27
18
159
76
83
850
Supermarket
27,605 SF
68
41
27
337
172
165
912
Drive -In Bank
3,829 SF
1 47
1 26
1 21
1 175
88
1 87
934
Fast -Food Restaurant w/ Drive Thru
2,154 SF
114
58
56
75
39
36
Totals:
1 425
232
193
1 884
440
444
UPDATED TRAFFIC ASSIGNMENT
The primary purpose of this TIA update is to analyze the impact of the updated development plan
on the study area intersections. In order to assess that impact, a new trip assignment was
prepared. This trip assignment relied on the trip orientation percentages used in the 2005 study
but routed all of the increased daycare traffic through Driveway 4, the northernmost driveway on
Randol Mill Road. This is the closest driveway to the proposed daycare and it was assumed that it
would offer the most attractive pick -up /drop -off access to parents of the daycare students.
Background Traffic
For the purposes of this update, the horizon year of 2012 used in the previous study was
maintained as the design year. In addition, after reviewing the 2009 traffic count data available
Mixed -Use Development TIA
Page 3
DeShazo, Tang & Associates, Inc.
December 29, 2009
from the City /Town of Southlake, it was determined that the 2012 background traffic volumes
used in the 2005 study yielded estimated annual growth rates of 3% to 12% (the growth rates
required for the 2009 traffic counts to achieve the 2012 projected levels) and, therefore, continue
to represent acceptable projections for the year 2012. These volumes are shown in Exhibits 2
and 3 (note that only Driveway 4, the northernmost driveway on Randol Mill Road and the
driveway closest to the proposed daycare, is studied).
Site Traffic
As stated earlier, the trip orientations used in the 2005 study were also used in this update.
Applying these orientations to the increased traffic associated with the proposed daycare and
adding this to the Driveway 4 site traffic from the 2005 report yielded the AM and PM peak hour
site traffic volumes shown in Exhibits 4 and S.
Total Traffic
The total AM and PM peak hour traffic volume estimates were calculated by combining the
background traffic volumes and the projected site traffic volumes. These volumes, shown in
Exhibits 6 and 7, will be used to determine the impact of the proposed daycare facility.
IMPACT ANALYSIS
Roadway Geometry
For this update, Randol Mill Road was assumed to retain its existing two -lane cross - section at its
intersection with Driveway 4. Driveway 4 was assumed to provide two exit lanes: a left- and a
right -turn.
Delay Calculation
The 2012 total (background - plus -site) traffic volumes were analyzed using the SYNCHRO 7 analysis
software and the results are summarized in Table 4. Detailed software output is provided in the
Appendix. The intersection capacity analysis shows that, even though the exiting left -turn traffic
will experience moderately high delays, Driveway 4 will continue to provide acceptable levels of
service to traffic on Randol Mill Road upon the addition of the daycare traffic.
Mixed -Use Development TIA
Page 4
DeShazo, Tang & Associates, Inc.
December 29, 2009
Table 4 — Intersection Capacity Analysis
Intersection
2012 Total Traffic
AM
PM
Driveway 4 @ Randol Mill
NB Left
A
A
EB Left
D
F
EB Right
B
B
KEY: A,B,C,D,E,F =Level of service for intersection approach movement.
# #. #= Control Delay (s /veh).
CONCLUSIONS
An update to the December 2005 traffic impact study for the proposed mixed -use development
located on the northwest corner of the FM 1709/FM 1938 intersection in the city /town of
Southlake, Texas, was conducted to analyze the impact of a change in the overall development
scheme (the addition of a 200 - student daycare in place of 27,354 SF of general office space).
The update conducted in this study shows an increase in the site - generated traffic volumes of 85
trips (25 %) during the AM peak hour and 29 trips (3.4 %) during the PM peak hour. The
subsequent analysis of site access — primarily focused on the impact of the proposed building
program on site Driveway #4 —shows the proposed site plan continues to provide acceptable
levels of service to traffic on the area roadway network.
END of MEMO
Mixed -Use Development TIA
Page 5
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2012 AM Peak Total Traffic
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2012 PM Peak Total Traffic
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APPENDIX
SYNCHRO Output
2012 AM Peak Hour Total Traffic
3: Driveway #4 & Randol Mill II
t
Movement EBL EBR NBL NBT SBT SBR
Lane Configurations
r
Volume (veh /h)
47
50
71
429
523 7
Sign Control
Stop
Free
Free
Grade
0%
0%
0%
Peak Hour Factor
0.92
0.92
0.92
0.92
0.92 0.92
Hourly flow rate (vph)
51
54
77
466
568 8
Pedestrians
Lane Width (ft)
Walking Speed (ft/s)
Percent Blockage
Right turn flare (veh)
Median type
None
None
Median storage veh)
Upstream signal (ft)
pX, platoon unblocked
vC, conflicting volume
1193
572
576
vC 1, stage 1 conf vol
vC2, stage 2 conf vol
vCu, unblocked vol
1193
572
576
tC, single (s)
6.4
6.2
4.1
tC, 2 stage (s)
tF (s)
3.5
3.3
2.2
p0 queue free %
73
90
92
cM capacity (veh /h)
191
519
997
Direction, Lane #
EB 1
EB 2
NB 1
SB 1
Volume Total
51
54
543
576
Volume Left
51
0
77
0
Volume Right
0
54
0
8
cSH
191
519
997
1700
Volume to Capacity
0.27
0.10
0.08
0.34
Queue Length 95th (ft)
26
9
6
0
Control Delay (s)
30.7
12.7
2.1
0.0
Lane LOS
D
B
A
Approach Delay (s)
21.4
2.1
0.0
Approach LOS
C
Intersection Summary
Average Delay 2.8
Intersection Capacity Utilization 67.8% ICU Level of Service C
Analysis Period (min) 15
12/28/2009
2012 PM Peak Total Traffic
3: Driveway #4 & Randoll Mill II
t
Movement EBL EBR NBL NBT SBT SBR
Lane Configurations
r
Volume (veh /h)
76
67
150
469
542 22
Sign Control
Stop
Free
Free
Grade
0%
0%
0%
Peak Hour Factor
0.92
0.92
0.92
0.92
0.92 0.92
Hourly flow rate (vph)
83
73
163
510
589 24
Pedestrians
Lane Width (ft)
Walking Speed (ft/s)
Percent Blockage
Right turn flare (veh)
Median type
None
None
Median storage veh)
Upstream signal (ft)
pX, platoon unblocked
vC, conflicting volume
1437
601
613
vC 1, stage 1 conf vol
vC2, stage 2 conf vol
vCu, unblocked vol
1437
601
613
tC, single (s)
6.4
6.2
4.1
tC, 2 stage (s)
tF (s)
3.5
3.3
2.2
p0 queue free %
32
85
83
cM capacity (veh /h)
122
500
966
Direction, Lane #
EB 1
EB 2
NB 1
SB 1
Volume Total
83
73
673
613
Volume Left
83
0
163
0
Volume Right
0
73
0
24
cSH
122
500
966
1700
Volume to Capacity
0.68
0.15
0.17
0.36
Queue Length 95th (ft)
91
13
15
0
Control Delay (s)
81.2
13.4
4.0
0.0
Lane LOS
F
B
A
Approach Delay (s)
49.4
4.0
0.0
Approach LOS
E
Intersection Summary
Average Delay 7.2
Intersection Capacity Utilization 77.0% ICU Level of Service D
Analysis Period (min) 15
12/28/2009