Item 7A (3) IA
Southiake Office Plaza
Southlake, Texas
Traffic Engineering Study
/ r' Y / i
:‘, :14-,'-'-'-' ' - ,;6
y
J • r 'tit ) t
y
4 '''''. ° '7"" , t ,
.ate *I�3i ' f r ,. '
j` � t' �
x Y`�T
Ait.'" r
....
SAVANT�j G ROUP
\ a"
/ ��P�E OF T 7/7/2014
*. -.* l
* * ■ , Engsh ineSmith er -in- EChargPTOE e:
JOSHUA D. SMITH i
' , 116285 ?Q : . J P..,
t, � OA � /CENS,..,-* ��
kk
Under a:
- o Pacheco contrct Koch
TABLE OF CONTENTS
Introduction 1
Data Collection & Existing Conditions 2
Traffic Counts & Signal Timings 2
Site Visit 3
Carillon Development 3
Projected Infrastructure Improvements 4
Projected Background Growth and Site Traffic 5
Projected Background Growth 5
Trip Generation 5
Trip Distribution and Assignment 6
Traffic Analysis 10
2014 Existing Traffic 10
2020 Background Traffic 12
2020 Build -Out Traffic 15
2025 Horizon -Year Traffic 17
Driveway Analysis 19
Driveway Spacing 19
Auxiliary Lane Analysis 19
Conclusions 20
Southlake Office Plaza Traffic Impact Assessment Page i
LIST OF TABLES
Table 1— Trip Generation 5
Table 2 — Intersection Level of Service Thresholds 10
Table 3 — Existing Level of Service Analysis 11
Table 4 — 2020 Background Level of Service 14
Table 5 — 2020 Build -Out Level of Service 15
Table 6 — 2025 Horizon -Year Level of Service 17
LIST OF FIGURES
Figure 1— Site Map 1
Figure 2 — Carillon Development Site Map 3
Figure 3 — Catchment Area Populations 6
Figure 4 — Trip Distribution 7
Figure 5 — Project Site Traffic Volumes 8
Figure 6 — Carillon Development Traffic Volumes 9
Figure 7 — 2014 Existing Traffic Volumes 11
Figure 8 — 2020 Background Traffic Volumes 13
Figure 9 — 2020 Build -Out Traffic Volumes 16
Figure 10 — 2025 Horizon -Year Traffic Volumes 18
Southlake Office Plaza Traffic Impact Assessment Page ii
SAVANT 0
INTRODUCTION
Savant Group Inc. (SGI) was retained to complete a traffic impact analysis for the Southlake
Office Plaza (project site) — a proposed medical facility and office development. The proposed
site is located on the southwest corner of White Chapel Boulevard and the SH 114 eastbound
frontage road, north of Countryside Court. The site location is shown in Figure 1.
FIGURE 1 —SITE MAP
T
'ow Y;�
A IIII
N. N
Q
-`
{^ Project
' 1ST Site
S IP - ' - '... _.. _.......„,
p _
Aerial Image Source: Google Earth
The project site is expected to contain a medical /dental office building and an office building:
the medical /dental office is expected to be sized at 51,000 square feet; the office building is
expected to be sized at 29,000 square feet. Site planning for the office building is still
preliminary and multiple options are under consideration, but 29,000 square feet of office
space for the later phase represents the most conservative assumption in terms of the site's
ultimate trip generation. The site will be accessed by two driveways, with one coming from
Countryside Court and the other from the SH 114 eastbound frontage road. The proposed site
plan is shown in Appendix A. For purposes of this study, the site is expected to be fully built
out by the year 2020. Per TxDOT requirements, analysis for a horizon year of 2025 will also be
considered as part of this study.
Southlake Office Plaza Traffic Impact Assessment Page 1
SAVANT . G Rut.) 1;
in addition to the project site, a large background development, Carillon, as well as various
infrastructure improvements along White Chapel Boulevard, were included in this study. The
Carillon development was included as fully built -out in the year 2020 analysis, while the
roadway improvements were assumed to also be complete for the 2025 horizon -year analysis.
This report is divided into five main sections which describe the steps taken to complete this
traffic impact assessment:
• Data Collection & Existing Conditions: explains the method for obtaining traffic counts,
signal timings, and existing roadway characteristics. This section also describes the
Carillon development and expected roadway improvements in detail.
❖ Protected Background Growth: explains the process for estimating background traffic for
future -year analyses, and includes the trip generation, distribution, and assignment
methodology.
• Traffic Analysis: includes the traffic analysis done for each scenario for the AM and PM
peak hours.
• Driveway Analysis: describes the steps taken in determining whether the site meets the
requirements of the City of Southlake and TxDOT, and determining which improvements
would be needed to meet those requirements.
• Conclusions: provides a summary of analysis results and makes final recommendations.
DATA COLLECTION & EXISTING CONDITIONS
TRAFFIC COUNTS & SIGNAL TIMINGS
Based on the location of the site, it was determined to study the following intersections that
provide access or are adjacent to the proposed development:
• Kirkwood Blvd. at White Chapel Blvd. (unsignalized)
• SH 114 Frontage Roads at White Chapel Blvd. (signalized diamond interchange)
• Countryside Court at White Chapel Blvd. (unsignalized)
• Highland St. at White Chapel Blvd. (unsignalized)
CJ Hensch & Associates, Inc. was contracted to collect turning movement counts at the listed
intersections. Turning movement counts were collected on Thursday, May 29, 2014 and June 3,
2014 and were aggregated into 15- minute counts for the AM and PM peak periods: the AM
peak period was from 7:00 -9:00 AM; the PM peak period was from 4:00 -6:00 PM. All of the
counts collected are shown in Appendix B.
Signal timing data for the intersection of the SH 114 Frontage Roads with White Chapel
Boulevard was obtained from TxDOT.
South Office Plaza Traffic Impact Assessment Page 2
SAVANT C1N G
SITE VISIT
A site visit was done during part of the PM peak period on Wednesday, June 4, 2014. The
existing roadway geometry was observed to verify satellite images of the area, and the traffic
signal operation and traffic patterns around the site were observed. During the site visit, a
considerable queue was noticed along southbound White Chapel Boulevard, stretching from
the four -way stop intersection with Highland Street to the SH 114 interchange; most of these
vehicles were coming from the SH 114 westbound frontage road.
CARILLON DEVELOPMENT
Also incorporated into this study was the Carillon development, which is currently partially
built, but is also expected to grow over the next few years; for purposes of this study, the
Carillon development is expected to be fully built -out by 2020. The Carillon development is
located north of the White Chapel /SH 114 interchange, and spans between White Chapel
Boulevard and Carroll Avenue. The full Carillon development site — including unbuilt portions
— is shown in Figure 2.
FIGURE 2— CARILLON DEVELOPMENT SITE MAP
L
•
Carillon
Development
A.-
-,a
Project
'Site = w
Aerial Image Source: Google Earth
Currently, the Carillon development includes a children's medical center (according to the
Carillon Development TIA, this medical center is 69,500 square feet), and around 24
townhomes and 90 single family homes; the development is expected to include additional
Southlake Office Plaza Traffic Impact Assessment Page 3
4
SAVANT, G Ro( _
townhomes and single family homes, as well as shopping, office, and hotel land uses. A more
detailed description of the sizes of each projected land use can be found in the trip generation
section of this report. The already constructed portions of the development were not included
in the analysis for this project, as it is presumed that those trips generated are already part of
the existing traffic condition.
PROJECTED INFRASTRUCTURE IMPROVEMENTS
Improvements are expected to be made along White Chapel Boulevard to improve traffic
operations between SH 114 and Highland Street. While these improvements may be
completed by the 2020 design year, the City requested a "worst- case" analysis assuming full
build -out of all known developments and a deferral of the roadway improvements until a later
date. Therefore, the improvements are only included in the 2025 horizon year analysis. The
improvements expected are listed below:
❖ A two -lane roundabout is expected to be built at the intersection of Highland Street and
White Chapel Boulevard. All approaches would feed into this roundabout, with the
exception of a channelized right turn at eastbound Highland Street.
❖ White Chapel Boulevard is expected to be widened to four lanes from SH 114 through
Highland Street.
• The left turn movement at eastbound Countryside Court is expected to be removed.
Instead, left- turning traffic would turn right onto southbound White Chapel Boulevard
and make a U -turn between Countryside Court and Highland Street.
According to the Mobility & Master Thoroughfare Plan, part of the Southlake 2025 Plan by the
City of Southlake, the following roadway improvements are expected within the study area:
❖ White Chapel Boulevard will be expanded to a four -lane divided arterial between
Southlake Boulevard and Dove Street
❖ Highland Street will be expanded to a three -lane undivided arterial east of White Chapel
Boulevard
❖ Kirkwood Boulevard will be extended as a four -lane divided arterial west of its
intersection with White Chapel Boulevard, roughly paralleling SH 114 on the north side.
Kirkwood Boulevard will also be extended farther east to connect with East Highland
Street, providing an additional outlet for Carillon development traffic that does not yet
exist today.
Southlake Office Plaza Traffic Impact Assessment Page 4
SAVANT c3 G ROUP
PROJECTED BACKGROUND G ROWTH AND SITE TRAFFIC
PROJECTED BACKGROUND GROWTH
To account for expected background growth in the analysis years 2020 and 2025, TxDOT AADT
counts were obtained from TxDOT's online statewide planning maps for points near the study
area. Estimated growth was then applied to each collected turning movement count. Special
consideration was made for turning movement counts north of the White Chapel /SH 114
interchange, as currently empty land in that area can be expected to develop between now and
2020. The following growth rates were assumed for this study:
❖ 4 %: applied to counts north of the White Chapel /SH 114 interchange yearly until 2020
❖ 2 %: applied to counts south of the White Chapel /SH 114 interchange yearly until 2020,
and applied to all counts yearly from 2020 to 2025
TRIP GENERATION
Generating traffic for proposed developments is typically based on information in the Trip
Generation, 9 Edition, 2012 and the Trip Generation Handbook, 2nd Edition, 2004, developed
by the Institute of Transportation Engineers (ITE). The rates and equations in these reports
were applied to the development to determine the anticipated trips generated from the
development where applicable.
Table 1 shows the AM and PM peak period trips projected for the project site and the Carillon
development; the trip generation analysis can be found in Appendix C.
TABLE 1 —TRIP GENERATION
Site Land Use (ITE code in AM Peak Trips PM Peak Trips
parentheses) Size
P ) In Out In Out
Medical /Dental Office (720) 51k sq. ft. 96 26 45 114
Project Site Office (710) (Future Expansion) 29k sq. ft. 62 9 19 92
Total 158 35 64 206
Shopping Center (820) 326k sq. ft. 199 122 635 687
Office (710) 278k sq. ft. 382 52 66 324
Hotel (310) 200 rooms 63 43 61 59
Carillon Townhomes (230) 24 units 3 13 13 6
Development Single Family Homes (210) 90 units 18 55 60 36
Total Residential 21 68 73 42
Total Commercial 644 217 762 1,070
Total 665 285 835 1,112
Southlake Office Plaza Traffic Impact Assessment Page 5
SAVANT q G RO u
The intensity of various land uses for the Carillon Development was taken from the traffic study
the City of Southlake provided for the development, dated May 19, 2008, and an addendum to
the study dated March 19, 2010. Trip generation rates were updated using the 9 Edition of
Trip Generation. Table 1 assumes that 75% of the residential land use represented in the
Carillon development traffic study has already been built and occupied.
TRIP DISTRIBUTION AND ASSIGNMENT
Trips beginning and ending within both the project site and the Carillon development were
assumed to come from four areas:
• White Chapel Boulevard, north of Kirkwood Boulevard
❖ White Chapel Boulevard, south of Highland Street
❖ SH 114, west of White Chapel Boulevard
❖ SH 114, east of White Chapel Boulevard
The potential catchment area for both sites was assumed to be within eight miles of the project
site in any direction, with the exception of the area north of Grapevine Lake. This catchment
area was divided into four parts, relative to the estimated catchment area for each access point
to the sites. U.S. Census Tracts were then used to estimate the population of each catchment
area. A map of the catchment areas with each area's population is shown in Figure 3.
FIGURE 3 — CATCHMENT AREA POPULATIONS
ff
_ 1) 01)0 Oak �V 1-______
--
i
,-
, I e sille
tY r ,, )N c 4 .:
V - 1 ;- "!, 4
40,633 1
- reashuu ask 1 � r �..
- Flower Moun� J �
0.uanOke
s
Troph Club j �
.. .... _ _ Westlake �IiLL°
7,839 1 I
ILL
r� 111,362 PP" (ao1 •Southlake 1
. - •Keller .,i Grapevine
!1 /
3f
G \ 117.015 -
/ —
/ \--Lt '•
I
Elul iUound Wd \ MO /
- - 1 I
h fi - - - ----1, j
I
Southlake Office Plaza Traffic Impact Assessment Page 6
SAVANT
The trip distribution used in this study was applied to both the project site and the expected
new trips to /from the Carillon development. The share of trips at each access point of the study
area is proportional to the population of each respective catchment area. The trip distribution
for this study is shown in Figure 4.
FIGURE 4 - TRIP DISTRIBUTION
I
- 1 ' ‘ _ _
1 - 1 f .. .
,
Carillon
`� Development
Project ,.:
Site A
!.: J .�_ y,e
d . tt
' ^ y — `fgh;anasrt
F n ro
I
P EA
i
6
Aerial Image Source: Google Earth
There was generally only one practical route between the site and each external point on the
study network. Trips which had the option of using either the SH 114 eastbound frontage road
or Countryside Court were distributed mostly toward using the frontage road.
At the Carillon development, trip assignment was different for residential and commercial
developments. For residential developments, trips were distributed mostly via Southmont
Drive, near the Children's Medical Center; commercial developments were assumed to be
located along White Chapel Boulevard toward the west end of the development — those trips
were distributed mostly via White Chapel Boulevard.
The assigned traffic volumes generated by the project site and the Carillon Development can be
found in Figure 5 and Figure 6.
Southlake Office Plaza Traffic Impact Assessment Page 7
SAVANT ES iROu
FIGURE 5 — PROJECT SITE TRAFFIC VO
a » ."` G
.. w ...y r y i, .. �
` �� 5 Kirkwood Blvd
0 (0)
, i m O
O O
I
AM 441
„ph 1
m
y n
2 o a
. ,
3 SH114W
•
0 (0)
0 (
64 (20)
:71:1, N t^Ov
p AM Kph (PM ‘Ph)
i Z.
4 =
N SH �) FR - 3
SH 114 EB FR 1 (5
� 0 (0) 13 (80) 114
of m
; f
N
`" -•.•,'., AM ,ph (PM aph AM Kph (PM op
7 [ 4
a
N 7
m N m
c ° e
4 m�
m V
is ..e., 8
a H v Coun tryside C rt Countryside Cr' 0 . r,,,,_. ,44,,-- 0 0( 0) �' 135 (6 2 (6)
(40)
'1*. P (0)
* AM PM . , AM .h PM .h
S 10
I ;
o, o = o
J: o o
. 8
3 Highland St
4 0 (0) 0 (0)
0 (0) 0 (0)
2:: N 0
.� F" ,�., • - - � `` • o AM Kph (PM VF
'4
Aerial Image Source: Goode Earth
Southlake Office Plaza Traf Imp act Assessment Page 8
i
SAVANT R U..J P
FIGURE 6 — CARILLON DEVELOPMENT TRAFFIC VOLUMES
a 1
C
...
O
' .... •'. # • 3 IGrkwood Blvd
#'r 3 (
sr 83 (241)
1
, 6
N
AM vph (PM eph)
2 I
m
m° m n
•
II V
3 SH114WB FR
67 (84)
24 (117)
0 (0)
o a
n
AM %ph (PM tph)
3 1
9
m m
' -', :-. *: 2
O
i m U
mow« + 2
ry
y SH 114 EB FR 3
; ,.w 98 (1 (0)
)
0 (0
0 (0)
n
1 , m o
a
m
t ° �. �
... 4 1
0
v AM eph (PM Kph)
ac
:= a
,, '� Co untryside Crt 3
4 -4 t
4.. r AM Wh (PM eph1
5 1
a
at o
Ti. ' o
r r p p
U
Highland St
II
0 (0) 0 (0)
ar.. -.r. 0 (0) 0 (0)
.
0 ( 0 (0)
.
.
•
p�p
AM mph (PM vph)
t • Aerial Image Source: Google Earth
Page 9
Southlake Office Plaza Traffic Impact Assessment
SAVANT
TRAFFIC ANALYSIS
Traffic was analyzed at each intersection of the study area for the AM and PM peak hours. The
following scenarios were analyzed:
• 2014 Existing Traffic
• 2020 Background Traffic: includes projected background growth and Carillon
background development traffic, without the Southlake Office Plaza site
• 2020 Build -Out Traffic: includes projected background traffic plus full site traffic for the
Southlake Office Plaza site
• 2025 Horizon -Year Traffic: includes projected background traffic and full site traffic. This
scenario also incorporated expected infrastructure improvements along White Chapel
Boulevard
Analysis of each existing and future scenario for AM and PM peak hours was done using
SynchroTM version 8 to perform a capacity analysis at each intersection. The capacity analysis
functions are based on the Transportation Research Board's Highway Capacity Manual (HCM),
2000. The HCM is a nationally recognized standard for performing capacity analyses. The
reports generated from each Syncrho model used are shown in Appendix D.
Capacity analyses are evaluated based on a level of service that ranges from A (excellent) to F
(poor). Levels of service A through D are generally considered acceptable and levels of service E
and F are considered unacceptable. The level of service thresholds in the Highway Capacity
Manual for signalized intersections and stop - controlled intersections are shown in Table 2.
TABLE 2 — INTERSECTION LEVEL OF SERVICE THRESHOLDS
Control Delay Per Vehicle (seconds)
LOS Stop- Controlled
Signalized Intersection
Intersection
A < 10 —< 10
B >10 and <_20 >10 and <15
C >20 and <_35 >15 and <_25
D >35 and _ <55 >25 and < _35
E >55 and _ <80 >35 and <_50
F LL >80 >50
2014 EXISTING TRAFFIC
The existing traffic scenario used collected traffic counts without any applied growth, and did
not consider the project site or any projected development at the Carillon development. The
traffic volumes for the scenario are shown in Figure 7. The AM and PM level of service analysis
at each intersection is shown in Table 3.
Southlake Office Plaza Traffic Impact Assessment Page 10
S
FIGURE 7 - 2014 EXISTING TRAFFIC VOLUMES
s I 1
°" m 0
n m a-,.
N
t
3 Kirkwood Blvd
9 (9)
42 (24)
1 m
4
'� n AM aph (PM ".ph)
2 I '
or m
2 [ T m O
0
m m
ir , '1 -3 k. V U
3 SH114WB FR
- ,ac..�r (2
40 161 (8186) 2)
306 (607)
m
n �
N
,�, AM eph (PM wh)
41*444. ''''- 4 3 I ,. ;
N
°.
_, SH 114 EB FR
.,._ 29 (42)
107 (146)
. 0 .
" *+. 2 a
AM eph (PM oph)
� 4
m m
m n a $2 n
Sitie .-+ -� ^� ." . ...
Countryside Crt m 3
4 (13)
A i
�� i j d
a ... n AM eph (PM eph)
5
7, i . o
14S-C. tif
S Highland St
194 (69) 23 (10)
y Ill ° . 126 (45) 14 (19)
151 (55) 38 (84)
a
m n
v - .. _ .._...
. _ _
__ f `,. - 1p AM eph (PM vph)
n ,- - ,. Aerial Image Source: Google Earth
Southlake Office Plaza Traffic Impact Assessment Page 11
SAVANT WU P
TABLE 3 — EXISTING LEVEL OF SERVICE ANALYSIS
LOS
Intersection Control Approach AM Peak Hour PM Peak Hour
Type Approach Overall Approach Overall
Kirkwood Blvd NB
Side Street * *
at White SB * A * A
Chapel Blvd Stop WB C B
SH 114 WB FR NB B B
Traffic
at White SB B B B E
Chapel Blvd Signal WB B F
SH 114 EB FR at NB A B
White Chapel Traffic SB B A B B
Blvd Signal _ EB A A
Countryside Ct NB
Side Street * *
at White SB * A * A
Chapel Blvd Stop EB B C
NB F D
Highland St at
Four -Way SB F F
White Chapel
Stop EB C F B F
Blvd p
WB B B
*Approach does not have any traffic control and is assumed to operate without delay.
Most intersections during both peak hours operated at a level of service of B or better. The
intersection at Highland Street performed at LOS F for both peak hours due to heavy traffic in
the northbound and southbound directions. The westbound approach at the SH 114 westbound
frontage road operated at LOS E due to heavy left- turning traffic at the westbound approach.
To improve conditions at the study intersections, the following changes are suggested:
❖ The PM signal timing should be optimized at the SH 114 interchange to provide more
time to the EB /WB ramps; this would result in an overall LOS C and no worse than LOS D
for any movement.
• At Highland Street, a temporary two -phase traffic signal would improve LOS to B in the
AM peak and LOS A in the PM peak.
2020 BACKGROUND TRAFFIC
The 2020 background traffic scenario includes background growth applied to existing traffic
counts, and adds traffic from the full build -out of the Carillon development. The traffic volumes
for the scenario are shown in Figure 8. The AM and PM level of service analysis at each
intersection is shown in Table 4.
Southlake Office Plaza Traffic Impact Assessment Page 12
SAVANT
FIGURE 8 BACKGROUND TRAFFIC VOLUMES
1
+�
s- vtionasikeow
B. •
Kirkwood Blvd
" '++►"�" "" 't„' 12 (18)
125 (265)
4
m
. I ,.g,' m N
n �D
AM <ph (PM eph)
2 1
i m
. ' p "" fir _. m m ci
SH114WB FR
228 (370)
_ 64 (929)
306 (607)
:
' 1".: m
AM eph (PM eph)
t 3 I ,..-6 >
m
o v
vi M � V
c
o
SH114FBFR 1
ik
/11111114
x _ 118 (129)
107 (146)
m
..
N
SI
• . _ ° AM Wh (PM Kph) )
>''' 4 I
Ot
T - m
lir 1.1_, - 4* e : := 2 2
couptryade Crt 3
.-� _ ..I 4 13
y 4
F . IN i * ''r
F.
°' AM ',ph (PM %ph)
0 5 I i iz
m
ES °
T. ' ' o
t r r
yq U
L t Highland St
194 (69) 23 (10)
_, 126 (45) 14 (19)
"` 151 (55) 38 (84)
N
- AM ‘ph (PM tph)
r ° Aerial Image Source: Google Earth
Southlake Office Plaza Traffic Impact Assessment Page 13
•
SAVANT 0 G Rol _ IP
TABLE 4 —2020 BACKGROUND LEVEL OF SERVICE
LOS
Intersection Control Approach AM Peak Hour PM Peak Hour
Type Approach Overall Approach Overall
Kirkwood Blvd NB * *
Side Street
at White SB * A * B
Chapel Blvd Stop WB D E
SH 114 WB FR NB B B
Traffic
at White SB B B C F
Chapel Blvd Signal WB B F
SH 114 EB FR at NB B B
White Chapel Traffic SB D C D C
Blvd Signal EB B B
Countryside Ct NB * *
Side Street
at White SB * A * A
Chapel Blvd Stop EB C F
NB F F
Highland St at
Four Way SB F F
White Chapel
Stop EB C F B F
Blvd p
WB B B
*Approach does not have any traffic control and is assumed to operate without delay.
With background growth but no new improvements, level of service deteriorates at several
locations when compared to the existing scenario. At Kirkwood Boulevard, the westbound
approach operates at LOS D during the AM peak and LOS E during the PM peak. The SH 114
westbound frontage road faces extreme congestion at its westbound approach. At the SH 114
eastbound frontage road, the southbound left turn movement operates at LOS F for both peak
hours. Left turns from Countryside Court also operate at LOS F during the PM peak. Lastly, LOS
at Highland Street remains at F for both peak hours.
To improve these conditions, the following improvements are suggested:
❖ At Kirkwood Boulevard, installing a traffic signal would improve conditions to LOS A in
the AM peak and LOS B in the PM peak without any widening. Widening White Chapel
to five lanes, based on preliminary analysis, would not improve LOS with the westbound
side street stop. This improvement would be borne by the Carillon retail /office
developer.
❖ At the SH 114 westbound frontage road, adding an extra lane on the westbound
approach and converting the phasing to a four -phase diamond operation would improve
LOS to D in the PM peak, with all movements operating no worse than LOS D. The four -
phase diamond phasing would also improve the eastbound frontage road LOS to C
during the PM peak.
Southlake Office Plaza Traffic Impact Assessment Page 14
SAVANTO(JPOIIP
• At Countryside Court, the eastbound left turn movement volume is low and under
capacity, so an improvement is not warranted.
• At Highland Street, the recommended temporary traffic signal would keep LOS at B for
AM and PM peaks.
2020 BUILD -OUT TRAFFIC
The 2020 build -out scenario includes background growth applied to existing traffic counts, as
well as full build -out of both the project site and the Carillon development. The traffic volumes
for the scenario are shown in Figure 9. The AM and PM level of service analysis at each
intersection is shown in Table 5.
TABLE 5 — 2020 BUILD -OUT LEVEL OF SERVICE
Control LOS
Intersection Approach AM Peak Hour PM Peak Hour
Type
Approach Overall Approach pproach Overall
Kirkwood Blvd NB * *
Side Street
at White Sto SB * A * B
Chapel Blvd p WB D E
SH NB B B
at White Traffic SB B B C F
Chapel Blvd Signal WB C F
SH 114 EB FR at Traffic NB B B
White Chapel Signal SB D C D C
Blvd EB B B
Countryside Ct NB * *
Side Street
at White Sto SB * A * B
Chapel Blvd p EB D F
Highland St at NB F F
White Chapel Four Way SB F F
F F
Blvd Stop EB C B
WB B B
—_s
*Approach does not have any traffic control and is assumed to operate without delay.
Compared with the 2020 background traffic scenario, there are few significant changes to LOS
in the 2020 build -out scenario. The exception occurs at Countryside Court, where eastbound
left- turning traffic is more significant with the addition of the project site, and causes a
significant increase in delay for that movement. As such, construction of a temporary median
wide enough to accommodate two -stage left turns should be considered.
The City will ultimately provide a "hooded" left turn lane to restrict left turns out of Countryside
Court as part of the White Chapel Blvd widening. Traffic exiting the Southlake Office Plaza via
Southlake Office Plaza Traffic Impact Assessment Page 15
SAVANT
FIGURE 9 — 2020 BU ILD -OUT TRAFFIC VOLUMES
R . 0
wa m
N
�. i r m n
....,.,.,,, .. * - t7 2
.r1lRt�
# r " . 3 Wrkwood Blvd
12 (18)
mm 125 (265)
i ^ c
m N
1 R
AM Kph (PM eph)
2 1
i
m -,o
- m g yy
ill
N '8 m
It -,.1. I iki s
SH114WB FR
228 (370)
64 (929)
370 (633)
F m
N r '
E AM Wh (PM )00 0 3
m
' ,,,,,,ii
µ ms« .. O
2 U
, ,i '' W SH114 ®FR
SH 114 ®FR 119 (134)
' ".. 274 (341) _. 42 (122)
6 i„,,,,,„ 23(9) 112 (193)
m m v
N
3 ,,.,
N N_
AM '.ph (PM %130) ° AM nph (PM vph)
7
I 3 _ [e
' m O c ii
[] m t0 Z
P" m s
r, m Countryside Crt Countryside Crt 3
'' , ''M.: 0 (0) 135 (55) 3 (23)
z 1 (6) 5 (3)
4 14 (53)
°i
AM •h PM •h) AM vph (PM •.ph)
5 1
m E �
E.... R, c
1
R,
U
2 c
Highland St
(P 194 (69) 23 (10)
1 (45) 14 (19)
a 151 26 (55) 38 (64)
r
m
. .; m
m n m
__ fi• '., .-- m AM vph(PM vph)
■ Aerial Image Source: Google Earth
Southlake Office Plaza Traffic Impact Assessment Page 16
SAVANT
the left turn would have to make a right turn followed by a U -turn, reducing the delay incurred
by making a direct left turn. However, U -turns will not be geometrically feasible for most
vehicles until White Chapel Blvd. is widened from 2 to 5 lanes. Constructing a temporary
median refuge area so that left turning vehicles may select gaps in southbound traffic, stop in
the median, and then select gaps in northbound traffic would improve conditions to LOS E for
the eastbound left turn movement during interim conditions.
The Highland St at White Chapel Blvd intersection could continue to operate with temporary
two -phase signal control under this scenario, with a resulting LOS B during both peak hours.
Alternatively, construction of the planned two -lane roundabout would result in LOS A
conditions during both peak hours, as per SIDRA software models that were used to analyze the
future roundabout. The results of the roundabout analysis can be found in Appendix E.
2025 HORIZON -YEAR TRAFFIC
The 2025 horizon -year traffic scenario includes full build -out for all developments, background
growth of the traffic counts, and expected infrastructure improvements along White Chapel
Boulevard. The traffic volumes for the scenario are shown in Figure 10. The AM and PM level of
service analysis at each intersection is shown in Table 6.
TABLE 6 — 2025 HORIZON -YEAR LEVEL OF SERVICE
Control LOS
Intersection Approach AM Peak Hour PM Peak Hour
Type Approach Overall Approach Overall
Kirkwood Blvd NB
Side Street * *
at White SB * A * C
Chapel Blvd Stop WB D F
SH 114 WB FR NB A A
at White Traffic Signal SB D C F F
Chapel Blvd WB C F
SH 114 EB FR at NB D E
White Chapel Traffic Signal SB A C A C
Blvd EB C D
Countryside Ct NB
Side Street * *
at White SB * A * A
Chapel Blvd Stop EB A B
NB ** **
Highland St at ** **
White Chapel Two Lane SB E
Blvd Roundabout EB ** **
WB ** **
*Approach does not have any traffic control and is assumed to operate without delay.
* *Roundabout approaches do not have any traffic control, and are not measured for level of service.
Intersection LOS is computed with Intersection Capacity Utilization
Southlake Office Plaza Traffic Impact Assessment Page 17
4
SAVAN G 1 0u P
FIGURE 10 — 2025 HORIZON YEA TRAFFIC VOLUMES
sr r° . 1 I
f r >
F � m°
--- .. . > i .. f U o
o
— v
, mo w,. �,•„�,. t
3 Kirkw Blvd
_ .« _yF= ` 12 (18)
125 (265)
;
v RI
. i � m o
h (PM 'Ph)
m
AM Kp
2 I i o
m o ,,
R
r m
m o
U m m
3 SH11 4062 4 449 ; i: BFR
400)
I
' ...lir; .:
v . 014)
697)
uo n
j " AM h ( PM'ph )
0
g ft
T o ,...F1
W
0
o m
' 2 U
a s
�'� " ti SH114EBFR 3
SH 114 EB FR ()
292 (364) - -- 45 121 (126)
23 (9) 11242361
23 (209
G N
Ti AM vph (PM eph)_ tO ° AM oph (PM oph)
I a
>
epo
3
7
T
N m
7 ^, y m
m v m
D O m m a
N
U
t
N Count Crt Count Crt 3
•
4,4 0 (0) 135 ( 55 ) 3(23)
1 (6) 5 (3)
40340441ii '.
7
a 14 (53)
AM •h PM AM vph (PM vp
s
n
n
U
_S
t
3
Highland St
214(76) 25(11)
139 (50) 15 (21)
2 f 167 (61) 42 (93)
y F m m
fal
4 —s AM uph (PM p •
r :; Aerial Image Source: Google Earth
Southlake Office Plaza Traffic Impact Assessment Page 18
SAVANT C\ O _
The major infrastructure improvement for this scenario is the conversion of the Highland Street
intersection into a two -lane roundabout. SIDRA software was used to analyze the roundabout,
and according to that analysis the roundabout would operate at LOS A for both the AM and PM
peak hours. With two lanes, the north and southbound movements operate at around half -
capacity during both peak hours, and the conflicting east- and westbound approaches are not
estimated to carry high volumes. The results of the roundabout analysis can be found in
Appendix E.
DRIVEWAY ANALYSIS
As part of this analysis, the project site driveways were evaluated to determine whether they
meet regulations made by the City of Southlake and TxDOT. Because the majority of future
peak hour trips on Countryside Court will be related to the Southlake Office Plaza site in the
future, Countryside Court was considered as a driveway for purposes of comparison with the
City's standards.
Along the SH 114 eastbound frontage road, the project site's driveway spacing with White
Chapel Boulevard and a driveway to the west was checked. The need for
acceleration /deceleration lanes at White Chapel Boulevard at its intersection with Countryside
Court was also checked.
DRIVEWAY SPACING
TxDOT's driveway spacing criteria, as per Table 2 -1 of the Access Management Manual, is 360
(edge of curb to edge of curb) based on the 45 mph speed limit on the frontage road. The same
spacing is required between driveways and adjacent cross streets as well as consecutive
driveways. Since only about 600 feet of frontage road is available between White Chapel Blvd
and the church driveway to the west of the site, the driveway spacing criteria cannot be met. A
variance must be requested from TxDOT. Information regarding any attempts to explore a
shared access agreement with the church to the west may expedite TxDOT's consideration of
the variance. Shifting the driveway to a point halfway between the existing driveway and White
Chapel Road would also improve the chances of the variance being accepted.
AUXILIARY LANE ANALYSIS
Southbound Right Turn from White Chapel Blvd. to Countryside Court: Section 5.4.a of City
Ordinance No. 634 states that right turn auxiliary lanes are required where 50 or more
veh /hour are anticipated for right turn ingress during a peak hour. Based on the AM volume of
87 veh /hr, a right turn deceleration lane will be required for the southbound right turn from
White Chapel Blvd to Countryside Court. As Countryside Court is just south of where the two
southbound lanes currently taper down to a single lane, and because ultimate widening to two
Southlake Office Plaza Traffic Impact Assessment Page 19
SAVANT
lanes each way south to Highland Street is programmed, the City will likely require widening to
two -full lanes south to Countryside Court plus the deceleration lane.
Northbound Left Turn from White Chapel Blvd. to Countryside Court: Section 5.4.e of City
Ordinance No. 634 states that left turn auxiliary lanes (turn bays) may be required where both
50 or more veh /hr are anticipated for left turn ingress during a peak hour and the product of
the projected left turn ingress volume and the opposing volume per lane exceeds 25,000 in any
design hour. Based on the projected 2020 AM northbound left turn volume of 79 veh /hr and
the projected 2020 southbound through volume of 643 veh /hr, the product would be 50,797 if
it is assumed that there will be one southbound lane in 2020 as in existing conditions. If two
southbound lanes are assumed by 2020, consistent with current plans for White Chapel Blvd.
widening, then the southbound volume per lane becomes 322 veh /hr and the product is
reduced to 25,438. Thus, a left turn bay may be required in either case.
The plans for the White Chapel Blvd. widening include a hooded left turn deceleration lane
approximately 100 feet long, but the City may require it to be constructed early as part of the
Southlake Office Plaza development. Capacity analysis in Synchro indicated that the planned
100 ft length of the turn bay should be sufficient to store the maximum 95th percentile queue of
39 ft which would occur during the PM peak hour in the interim condition with only one
opposing southbound lane creating fewer gaps for northbound left turning traffic than will be
the case in the ultimate condition.
Eastbound Right Turn from SH 114 Frontage Road to Site Entrance: The TxDOT Access
Management Manual specifies in Table 2 -3 that deceleration lanes are required where right
turn ingress volumes are expected to be in excess of 60 veh /hr during a peak hour on roadways
with posted speeds less than or equal to 45 mph. Based on the 45 mph posted speed of the
eastbound SH 114 frontage road and the maximum AM peak hour right turn volume of 23
veh /hr to the site driveway from the eastbound SH 114 frontage road, no deceleration lane will
be required.
Northbound Right Turn from Site Entrance to Eastbound SH 114 Frontage Road: The TxDOT
Access Management Manual specifies in Table 2 -3 that acceleration lanes are required where
right turn egress volumes are expected to be in excess of 200 veh /hr during a peak hour. Based
on the maximum PM peak hour right turn volume of 160 veh /hr from the site driveway to the
eastbound SH 114 frontage road, no acceleration lane will be required.
CONCLUSIONS
The proposed Southlake Office Plaza is expected to generate 193 trips during the AM peak and
270 trips during the PM peak. The Carillon development is expected to add 950 trips during the
Southlake Office Plaza Traffic Impact Assessment Page 20
SAVANT
AM peak and 1,947 trips during the PM peak, and is more significant than the Southlake Office
Plaza site in creating congestion within the study area. The following improvements within the
study area are suggested to be constructed by the Southlake Office Plaza developer:
❖ Construct a southbound right turn lane from White Chapel Boulevard onto Countryside
Court. Due to the relatively short distance between Countryside Court and the SH 114
eastbound frontage road (approximately 300') the length of the right turn lane should
extend the entire distance of the link.
❖ Construct a 100' northbound left turn lane with 50' taper from White Chapel Boulevard
to westbound Countryside Court. The design should match the current plans for this
lane in the City's project for widening White Chapel Blvd.
• In lieu of constructing the above - mentioned northbound left turn lane as a "hooded"
left turn lane in the interim condition prior to White Chapel Blvd. widening to five lanes,
provide a temporary refuge area with two -way center left turn lane striping in the
median just north of the intersection with Countryside Court. The refuge area should be
at least 10 ft wide for a distance of at least 100 ft north of the intersection to allow for
staging of two -stage left turns from Countryside Court.
It is also noted that a variance will be required from TxDOT to construct the Southlake Office
Plaza driveway along the SH 114 eastbound frontage road.
The following improvements in the study area are suggested for implementation by the City or
other developers:
• Install a two -phase traffic signal at the intersection of White Chapel Boulevard and
Highland Street. This would greatly improve level of service for north /southbound
traffic at this intersection until the planned two -lane roundabout can be constructed.
• Add a lane to the westbound approach of the intersection of White Chapel Boulevard
and the SH 114 westbound frontage road, and change that intersection's phasing to a
four -phase diamond. This would especially improve performance of the westbound left -
turn movement at that intersection.
❖ Install a traffic signal at the intersection of Kirkwood Boulevard and White Chapel
Boulevard. This would decrease delay for side - street traffic at the intersection, which is
expected to grow as the Carillon development builds out. This improvement will be
more practical if — according to Southlake's master thoroughfare plan — Kirkwood
Boulevard is expanded to a four -lane divided arterial that continues westward from the
intersection.
Southlake Office Plaza Traffic Impact Assessment Page 21