Pedestrian Signal Safety - AAA Foundation for Traffic Safety

Figure H-2 shows the overall average vehicle delay (AVD) and intersection LOS under various
peak-hour traffic volume and pedestrian walking speed scenarios (3.00, 3.50, 4.00 ft./sec. and base
conditions).
Figures H-3, H-4, and H-5 show the major street and minor street approach AVD (in sec.) under
walking speeds of 3.00 ft./sec., 3.50 ft./sec., and 4.00 ft./sec., respectively. Table H-13 shows the
overall, major street approach, and minor street approach intersection LOS and AVD (in sec.) under
various peak-hour traffic volume scenarios and under pedestrian walking speeds of 3.00 ft./sec., 3.50
ft./sec., and 4.00 ft./sec.
Table H-13 shows there was a uniform increase in average delay per vehicle (ADPV) for the
volume scenario that was 5 percent above existing volumes. There was a greater vehicular delay at
pedestrian walking speeds of 4.00 ft./sec., 3.50 ft./sec., and 3.00 ft./sec. (in that order). The ADPV
was 72 sec., 68 sec., and 55 sec., respectively. This trend remained the same for volume scenarios to
10 percent and 15 percent above existing volumes.
The total intersection LOS decreased from LOS D to LOS F under the 3.00 ft./sec. walking speed
scenario when existing volume conditions were compared to the modeled increase of 10 percent
above existing volume conditions. Concomitantly, there was a corresponding increase in ADPV of 75
sec.
An incremental increase of another 5 percent of peak-hour volume (to 15 percent above existing
volumes) at the 3.00 ft./sec. pedestrian walking speed added 47 sec. to the ADPV. Thus, from existing
volume conditions to a modeled increase of 15 percent over existing volumes, there was a reduction
of two LOS designations (from LOS D to LOS F) and a corresponding increase in 122 sec. for ADPV.
Under the 3.50 ft./sec. pedestrian walking speed scenario, the delay increased at a greater rate than
at the 3.00 ft./sec. scenario until traffic volumes were increased between 5 and 10 percent. This
occurred because the 3.00 ft./sec. scenario provided more green time for the minor street due to the
increase in the pedestrian clearance interval for the parallel pedestrian movement. Under the 3.50 ft./
sec. pedestrian walking speed scenario and under a scenario that increased existing volumes by 15
percent, the total intersection LOS decreased from LOS D to LOS F and there was a corresponding
increase in 108 sec. for ADPV.
At the 4.00 ft./sec. pedestrian walking speed scenario, a large increase in ADPV occurred at the
existing level to 5 percent above existing volume conditions (17 sec.), followed by smaller increases
exhibited in the volume level modeled 5 to 10 percent above existing conditions (4 sec.) and in the
volume level modeled 10 to 15 percent above existing conditions (6 sec.). The total increase in
average intersection delay per vehicle from the existing volume condition level to 15 percent above
the existing volume condition level was 28 sec. and there was a reduction of one LOS designation
from LOS E to LOS F. Note that the difference in the ADPV between 15 percent above the existing
volume and the existing volume condition at the 3.00 ft./sec. and 3.50 ft./sec. pedestrian walking
speed scenarios was 94 sec. and 80 sec., respectively.
Major Street Approaches
The range in ADPV under existing volume conditions as compared to a modeled increase of 15
percent above existing volumes for the 3.00 ft./sec. walking speed assumption was 47 sec. to 219
sec. (this represented an increase in average delay of 172 sec.). LOS was reduced from LOS D
under existing volume conditions to LOS F when the volumes were increased to 15 percent above
existing volumes.
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