TR9701-CS 970415 (2)ki
Sverdrup
CIvII, Inc. - Dallas, Texas Office
4311 Oak Lawn Ave. ♦Suite 300 + Dallas, TX 75219 ♦ Tele: (214) 520 -2116 ♦ Fax: (214) 521 -3539
TECHNICAL MEMORANDUM April 15, 1997
TO: Tony Tramel
Dallas County c/o Parsons Brinckerhoff
1701 North Market Street
Suite 410
Dallas, TX 75202
FROM: Mark G. Goode, III, P.E.
SUBJECT: Proposed Control Area - Southern Section
Job No. 13776
Sverdrup Civil, Inc. has completed an analysis of a section of Belt Line Road and Denton Tap Road
in the cities of Irving and Coppell, Dallas County, Texas. The study boundaries are the intersection
of Denton Tap Road and Parkway Boulevard on the north and the intersection of Belt Line Road and
Oakdale Road on the south. The study area is approximately 14 miles long and includes 34
intersections (see Figure 1). Most of the intersections have existing traffic signals. Two of the
intersections are anticipating traffic signals in the near future to support development that is
underway.
Traffic data have been collected, including hourly directional machine counts, peak hour manual
turning movement counts and travel time runs. Field observations have been made to determine
intersection geometric conditions, lane usage, signal types and presence or absence of pedestrian
signalization.
Proposed Control Area Boundary:
The proposed control area boundary for the southern section is shown in Figure 2. The section
includes the following intersections:
• Belt Line Road / Valley View Lane
• Belt Line Road / S11 161 Westbound Frontage Road
• Belt Line Road / SH 161 Eastbound Frontage Road
• Belt Line Road / Story Road
Sverdrup 4311 Oak Lawn ♦ Suite 300, LB6 ♦ 75219 ♦ Phone: (214) 520 -2116 ♦ Fax: (214) 521 -3539
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O SIONALIZEO
INTERSECTION
Sverdrup 4311 Oak Lawn ♦ Suite 300, LB6 ♦ 75219 ♦ Phone: (214) 520 -2116 ♦ Fax: (214) 521 -3539
Civil, Inc. Dallas, Texas Page 3
1 [� Figure 2 '"11
l A nntrnrea Boundary Limits
• Belt Line Road / Walnut Hill Lane
• Belt Line Road / Country Club Road
• Belt Line Road / Northgate Drive
• Belt Line Road / Finley Road
• Belt Line Road / Rochelle Road
• Belt Line Road / Strait Street
• Belt Line Road / Grande Bulevar
• Belt Line Road / Irving Mall Entrance
• Belt Line Road / SH 183 Westbound Frontage Road
• Belt Line Road / SH 183 Eastbound Frontage Road
• Belt Line Road / Willow Creek Drive
• Belt Line Road / Pioneer Drive
• Belt Line Road / Conflans Road
• Belt Line Road / Rock Island Road
• Belt Line Road / Shady Grove Road
• Belt Line Road / Oakdale Road
With few exceptions, most of the signals in the section of Belt Line Road south of the SH 114
interchange are fairly close together. In particular, the intersections around the Irving Mall are very
closely spaced, and must be coordinated. The only possible locations for non - coordinated signals
are at the north end and south end of the control area. The spaces between Valley View Lane and
the SH 161 Westbound Frontage Road; Rock Island Road and Shady Grove Road; and Shady Grove
Road and Oakdale Road. However, at this time we are recommending that these stretches of
roadway be coordinated if possible due to the apparent demand of the traffic through these sections.
If at some point the progression in the more critical sections is adversely affected by the inclusion
of these locations, recommendations will be made to split the southern control area into two or more
sub - sections. An additional factor that lead to the decision to use the proposed limits for this control
area was one of the outputs provided by the computer program Synchro Professional. This output,
called the "Coordinatability Factor" is an indication of the recommended areas of coordination based
on travel time between the intersections, traffic volumes, platooning of the vehicles, main street
volumes and differences in natural cycle lengths.
Proposed Coordination Across City Limits:
The proposed control area only includes traffic signals in the City of Irving. Therefore, no
coordination across city limit lines will be necessary.
Sverdrup 4311 Oak Lawn ♦ Suite 300, LB6.75219 ♦ Phone: (214) 520 -2116 ♦ Fax: (214) 521 -3539
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Proposed Cycle Lengths:
1 ""N
Based on the traffic volumes and geometric conditions, we propose to use the following approximate
cycle lengths to get good progression along this section of Denton Tap Road and Belt Line Road:
Time of Day
AM Peak Hour
Noon Peak Hour
PM Peak Hour
Saturday Afternoon
Late Evening Off Peak
Off Peak
Start / End Times
7:00 AM -9:00 AM
11:30 AM- 1:30 PM
4:30 PM -6:30 PM
12:00 PM - 5:00 PM
6:30 PM - 10:00 PM
All Other Times
Cycle Length Ranee
80 - 100 sec.
80 - 90 sec.
100 - 130 sec.
100 - 150 sec.*
75 - 90 sec.
75 - 90 sec.
The long cycle lengths will only be needed in the immediate vicinity of the Irving Mall.
Therefore, the cycle lengths at the other intersections in the southern control area will operate
on cycles that are % the proposed cycle length of the Irving Mall intersections.
Due to the fairly bidirectional nature of the traffic through this section, timing plans will be proposed
that provide bidirectional flow, and may favor one direction or the other as area volumes dictate.
Preliminary Measures of Effectiveness:
The computer programs being used for this analysis are PASSER II and Synchro Professional.
These programs provide a number of measures of effectiveness to evaluate a proposed timing plan
prior to implementing it in the field. In particular, "Progression Band Widths" and "Percentile
Delay" (in seconds per vehicle) will be used to evaluate the projected effectiveness of the proposed
timing plans.
Recommended Hardware Improvements:
The existing hardware in this control area appears to be adequate to implement the proposed phasing.
Sverdrup 4311 Oak Lawn ♦ Suite 300, LB6 ♦ 75219 ♦ Phone: (214) 520 -2116 ♦ Fax: (214 Pa l 353
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At the intersection of Belt Line Road and the IH 635 Eastbound Ramp, the eastbound approach to
the intersection is striped for a dedicated left -turn lane and a lane that allows, left turns, throughs and
right turns. Considering the very heavy right -turn movement in the AM Peak Hour (over 500
vehicles between 7:15 and 8:15 AM), this approach would be more efficiently served by a dedicated
right -turn lane and a lane that allows through and left -turn movements. In addition, a right -turn
overlap could be used at this location with the installation of an additional signal head.
Progression along this stretch or roadway is vastly improved if lead -lag operation can be
implemented at the intersection of Belt Line Road and Regent Boulevard. This can be accomplished
without introducing the "Yellow Trap" effect through the use of Dallas display left -turn heads or
non - permissive heads.
If these proposed improvements are performed prior to the implementation of the recommended
timing, the proposed timing will provided much more efficient service to the traveling public.
S verdrup 4311 Oak Lawn ♦ Suite 300, LB6.75219 ♦ Phone: (214) 520-2116 ♦ Fax: (214) 521 -3539
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