Pedestrian Signal Safety - AAA Foundation for Traffic Safety

where:
W = duration of WALK indication
D 4 = distance between the center of the corner radius to the center of the farthest lane
V p = walking speed
Y = yellow interval duration
R = all-red interval duration
It should be noted that the recommendations of Kochevar and Lalani have not been adopted by
MUTCD (Kochevar and Lalani 1985).
Virkler conducted field studies of high-volume two-way pedestrian crossings in Brisbane, Australia
to determine appropriate pedestrian signal timing parameters. Based on observations of platoons of
pedestrians crossing at four locations, Virkler recommended the following equation for calculating the
WALK interval:
⎛ N1
⎞
WALK duration = 3 . 2 s + ( 0.
57 s / ped / m)
× ⎜ ⎟
⎝ W ⎠
where:
W = crosswalk width, in meters
N = primary platoon size
When more than 20 people are expected in a platoon, Virkler recommended the following equation to
determine the total pedestrian phase (WALK plus FDW):
L
WALK + FDW = 3. 2s
+ + ( 0.
27 s / ped)
× N
1.
2 m / s
where:
N = primary platoon size
L = length to be crossed, in meters
This recommendation also has not been adopted by MUTCD (Virkler 1998).
Leading Pedestrian Intervals
1
Zegeer et al. suggested the use of a leading pedestrian interval (LPI). At intersections equipped with
LPIs, pedestrians are given the WALK indication before motorists on the parallel approach receive
the green indication. Pedestrians are more visible to motorists because they already are in the
intersection before motorists start their maneuvers (Zegeer et al. 2001).
In Guidelines and Recommendations to Accommodate Older Drivers and Pedestrians, Staplin,
Lococo, Byington, and Harkey also recommend using an LPI at intersections with high pedestrian
volumes, high turning-vehicle volumes, and no-turn-on-red control for parallel traffic. The following
formula is provided for calculating the LPI duration:
( ML + PL)
LPI =
2.
8
37