Pedestrian Signal Safety - AAA Foundation for Traffic Safety

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COUNTDOWN PEDESTRIAN SIGNAL DEVICES
Page Two
Table 1
Typical Pedestrian Crossing Times at 4.0 feet per second and 6.0 feet
per second
Number of Lanes To Cross (12 foot lanes plus 12 feet for corner radii)
2 Lanes To Cross 3 Lanes To Cross 4 Lanes To Cross 5 Lanes To Cross
Typical Distance 36 feet 48 feet 60 feet 72 feet
Time @ 4.0 ft/sec 9 seconds 12 seconds 15 seconds 18 seconds
Time @ 6.0 ft/sec 6 seconds 8 seconds 10 seconds 12 seconds
Time Difference 3 seconds 4 seconds 5 seconds 6 seconds
The time difference reflects extra time that a fast-walking person
theoretically has to work with. The table demonstrates the
increased usefulness of the device as the crosswalk distance
gets longer, especially in cases of extreme length. The longest
crosswalks that we operate (NYSDOT crosswalks across West
Ridge Road at Hoover Drive and Buckman Road) have a
clearance time of 30 seconds, can be walked in 20 seconds at
6.0 feet/second, and have a time difference of 10 seconds. They
have countdown pedestrian signals in place, and the value of
them is apparent.
Another consideration is the influence of conflicting vehicles that could delay a
pedestrian briefly during the flashing “DON’T WALK” interval. Locations with heavier
right- and left-turning vehicle volumes have a higher potential to delay a pedestrian’s
crossing. The time-remaining information would be helpful in this situation to reassure a
pedestrian that there is still adequate crossing time available for the completion of the
crossing.
The following guidelines are recommended for the placement of countdown pedestrian
signals.
1. PCD devices are recommended for the longer crossing lengths where crossing time
variance is greatest. A suggested threshold is at least 60 feet of crossing distance.
2. PCD devices are recommended where the right-turning and left-turning volumes
that conflict with the crosswalk are high. A suggested threshold is a combined 400
vehicles per hour (adding the conflicting right and left turning vehicle volumes
together).
In considering whether to install the devices, I would suggest that the location meet at
least one and preferably two of the above thresholds.
Although the devices could also be considered where the pedestrian volumes are high,
the better adjustment for this situation is to add more “walk” start up time. Therefore, the
primary need for the devices should be based on the two criteria listed above. 263
JRP:jrp
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