Pedestrian Signal Safety - AAA Foundation for Traffic Safety

EFFECT OF CHANGING WALKING SPEEDS ON PEDESTRIAN CLEARANCE TIMES
Table G-11 displays the required pedestrian signal times for different walking speeds and the time
available for that movement at each of the intersections studied. Table G-11 presents the ˝ symbol
where the total pedestrian signal time exceeded the available minimum green time. Key findings
related to pedestrian WALK clearance time durations for this case study intersections included:
• The pedestrian intervals exceeded the available green times for the 3.00 ft./sec., 3.50 ft./sec.,
and 4.00 ft./sec. scenarios in four of four crosswalks at the case study intersection.
Table G-11. Pedestrian WALK and clearance time durations for case study intersection in Salt Lake
City, Utah.
Approach/
crosswalk
Northbound/
south
Southbound/
north
Eastbound/
west
Westbound/
east
Length
(ft.)
Clearance time (sec.)
3.00
ft./sec.
3.50
ft./sec.
TRAFFIC OPERATIONS ANALYSIS
4.00
ft./sec.
Clearance time with 7-sec.
WALK (sec.)
[total WAL K time]
3.00
ft./sec.
3.50
ft./sec.
4.00
ft./sec.
Available
green
(sec.)
103 34 29 26 41˝ 36˝ 33˝ 31
112 37 32 28 44˝ 39˝ 35˝ 31
66 22 19 17 29˝ 26˝ 24˝ 23
78 26 22 20 33˝ 29˝ 27˝ 23
Table G-12 shows the intersection operational and geometric characteristics for the Salt Lake City
case study intersection. Figure G-3 shows the overall average vehicle delay (AVD) and intersection
level of service (LOS) under various peak-hour traffic volume and pedestrian walking speed scenarios
(3.00, 3.50, 4.00 ft./sec. and base conditions).
Figures G-4, G-5, and G-6 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 G-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.
There was no change in the overall LOS (LOS C remained the same) when comparing the modeled
decrease in volumes of -10 percent of existing volumes to a modeled increase of 15 percent above
existing volumes. There was a maximum increase of 4 sec. in terms of average delay per vehicle
(ADPV) under any of the volume or walking speed scenarios when comparing existing volume
conditions to a modeled increase of 15 percent above existing volumes. The graph included in Figure
G-3 shows there was a uniform increase in ADPV as peak-hour volumes increased.
203