Pedestrian Signal Safety - AAA Foundation for Traffic Safety

148
Table D-10. Pedestrian WALK and clearance time durations for case study intersection in
Minneapolis, Minnesota.
Approach/
crosswalk
Northbound/
south
Southbound/
north
Eastbound/
west
Westbound/
east
Length
(ft.) 3.00
ft./sec.
Clearance time (sec.)
3.50
ft./sec.
4.00
ft./sec.
Clearance time with 12-sec.
WALK (sec.)
3.00
ft./sec.
3.50
ft./sec.
4.00
ft./sec.
Available
green (sec.)
75 25 21 19 37˝ 33 31 34
78 26 22 20 38˝ 34 32 34
3 18 15 13 30˝ 27 25 28
50 17 14 13 29˝ 26 25 28
TRAFFIC OPERATIONS ANALYSIS
Table D-11 shows the intersection operational and geometric characteristics for the Minneapolis/
St. Paul case study intersection. Figure D-4 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 D-5, D-6, and D-7 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 D-12 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.
When comparing existing volume conditions to a modeled increase of 10 percent above existing
volume conditions, there was a decrease of one LOS designation (from LOS C to LOS D) with a
corresponding increase in average delay per vehicle (ADPV) of 14 sec. under the 3.00 ft./sec. walking
speed scenario. An incremental increase of another 5 percent of peak-hour volume to the 3.00 ft./
sec. walking speed lowered the LOS from D to E and added 7 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 C to E) and a corresponding increase of approximately 21 sec.
for ADPV.
Under the 3.50 ft./sec. and 4.00 ft./sec. walking speed scenarios, under existing volumes to an
increase of 15 percent of existing volumes, there was no change in LOS (LOS C remained the same);
however, there was a corresponding increase in ADPV of approximately 5 sec. and 4 sec. under the
3.50 ft./sec. and 4.00 ft,/sec. walking speed scenarios, respectively.
In summary, the 3.00 ft./sec. pedestrian walking speed, as compared to the 3.50 ft./sec. and 4.00
ft./sec. pedestrian walking speeds, had a greater negative impact on vehicular traffic operations at the
case study intersection.