Item 6B TNP N White Chapel Design Study Memo 11-04-09X-? TEAGUE NALL AND PERKINS
Civil Engineering Surveying Landscape Architecture Planning
Memorandum
To: Gordon Mayer, P.E.
From: Robert Jenkins, P� l�
cc: W
Date: November 4, 2009
Re: SLK09292 - White Chapel Design Study
Introduction
Traffic engineering services have been provided to support design decisions for
widening White Chapel Boulevard. These involved collecting traffic data; projecting
traffic growth; and evaluating capacity and control needs at the key intersections with
Highland Street, North Access Drive to the High School/Ascot Drive, South Access Drive
to the High School, and Chapel Downs Drive. The intersection at Highland Street was
evaluated for traffic signal and roundabout operations.
Data Collection and Projection
Turning movement counts were collected at the four intersections identified above.
Twenty-four hour counts were collected on White Chapel approaches/departures to and
from Highland and on Highland approaches. The 24 hour counts at Highland were
grown at 6% to establish volumes in 2012, and these were used to evaluate signal
warrants for the widened intersection. Figure 1 shows the existing a.m. peak and
p.m. school peak turning movement counts.
Future traffic volumes (2019) were estimated by growing background traffic and
estimating school trips at capacity. Special consideration was taken while growing
these counts. New student drivers during the spring semester were taken into account;
school trip growth was stopped after the school reached maximum capacity; and
background trips were grown at a rate of 6%. Existing patterns and a series of
extensive spreadsheets were used as the basis for distributing school trips. Figure 2
shows the projected 2019 a.m. peak and p.m. school peak turning movement counts
with White Chapel reconstructed to four lanes divided.
Existing Conditions and Observations
White Chapel Blvd. currently serves as a two lane undivided roadway with left turn bays
at all study intersections. South of Chapel Downs Drive and north of Ascot Drive,
school zone flashing beacons reduce the travel speed from 40 MPH to 20 MPH during
school peak hours. The current traffic control devices allow traffic to flow continuously
from FM 1709 to Highland Street.
1100 Macon Street Fort Worth, Texas 76102 817.336.5773 phone 817.336.2813 fax
Item 613 TNP White Chapel Design Study Memo www.tnp-online.com
Figure 1 - White Chapel Blvd.
2009 Peak Hour Volumes
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Item 613 TNP White Cha el Desi n Stud Memo
Nm TEAGUE NA L AND PERKINS
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Figure 2 - White Chapel Blvd. 2019
Peak Hour Volumes
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The Highland intersection currently exists as an all way stop operation and meets
multiple traffic signal warrants as an intersection of two lane roadways. Installing a
traffic signal can create longer gaps in thru traffic which will benefit east -west
movements at intersections to the south. The east -west movements at the school
Access Drives currently function at congested levels of service.
The southbound traffic passing through the North Access Drive of the School
intersection can benefit from the addition of a right turn bay. In addition, restriping the
eastbound approach to a left and thru along with a right only lane will also improve the
functionality of this intersection.
Operations Analysis
Synchro 7 and SimTraffic software were used to model the intersection operations
between Highland Street and Chapel Downs Drive. SIDRA INTERSECTION 4 software
was used to evaluate the operation of a roundabout at the Highland Intersection.
Future Roadway Improvements
The study took into account the widening of White Chapel Blvd to a four lane divided
roadway with left turn bays and the previously mentioned improvements like those at
the North Access Drive/Ascot Drive. A signal warrants check of the Highland
intersection in 2012, when the new 4 lane facility is in place, suggests that Warrants 2,
3, and 8 will be met.
Recognizing that Traffic at the Highland intersection will ultimately experience
undesirable delays under an all -way stop operation, it is appropriate to either signalize
or reconfigure the intersection to meet traffic growth. Constructing a roundabout for
this intersection appears to be a legitimate choice. A roundabout with two-lane
approaches on White Chapel and single lane approaches on Highland was analyzed with
SIDRA for the projected 2012 and 2019 a.m. peaks. Table 1 compares measures of
effectiveness for the a.m. peak roundabout and signal operations. It shows that the
roundabout may be the best choice in terms of operations, but the signal will handle
the 2019 projections if the roundabout is not feasible in terms of ROW and construction
costs.
The School's North Access Drive/Ascot Drive intersection will function at an undesirable
level of service due to background traffic growth on White Chapel and traffic generated
by the fully enrolled Carroll High. A traffic signal, along with the previous
recommendations, is recommended.
The School's South Access Drive intersection will experience a heavy northbound left
turn movement which requires ample storage; a 4 lane roadway section with a Two -
Way Left Turn Lane is recommended between this intersection and Chapel Downs
Drive.
At the Chapel Downs Drive intersection, the east -west volumes are relatively low; these
movements will benefit from gaps generated by the traffic signal at the North Access
Drive/Ascot Drive intersection, therefore the existing two way stop sign operation can
remain.
Page 4
Item 6B TNP White Chapel Design Study Memo
Table 1 — Comparison of Signal and Roundabout for Highland Intersection
This provides you with a brief overview of what we think can be expected and what
some of your options are. Let me know if you need further details/data in regard to the
analysis. When you and Bob are ready, we can meet to discuss the improvement
options and implementation timing.
Page 5
Item 6B TNP White Chapel Design Study Memo
Movement Los / Approach
Control
Configuration I
Lefts
East oun I
I Ylirus I Rightsi
Soultildmund
Left
I Thms
I Rigilvilts
I Westhound
I Lefts I
Thrus I
RightsiLefts
Nort oun
I Trus I Rig its
2012 AM Peak
LOS
Avg Delay (sec
95% Queue (ft)
2019 AM Peak
LOS
C
C
A
B
B
C
C
B
A
Avg Delay (seel
30.1
34.1
8
14.9
17.1
22.7
26.4
13.7
6.6
95% Queue (ft)
2012 AM Peak
86
83
10
222
1
8
26
36
83
LOS
B
A
A
B
A
A
B
A
A
B
A
A
Avg Delay (sec)
12.6
6.1
7.2
12.9
5.8
7.7
112
4.7
5.8
133
6.1
8.1
95% Queue ft
79
79
79
42
42
42
1 9
9
9
47
1 48
48
2019 AM Peak
LOS
C
8
6
8
A
A
8
A
A
B
A
A
Avg Delay (sec
20.2
13.8
14.9
13.4
6.2
8.1
12-5
6.1
T1
14.1
6.9
8.8
95% Queue (ft)
227
227
227
67
68
68
17
17
17
88
90
90
This provides you with a brief overview of what we think can be expected and what
some of your options are. Let me know if you need further details/data in regard to the
analysis. When you and Bob are ready, we can meet to discuss the improvement
options and implementation timing.
Page 5
Item 6B TNP White Chapel Design Study Memo