Samuel Tignor P.E.
McLean VA
stignor@aol.com
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In the April 2013 ITE Journal on page 39 there is an interesting article by Michael Koslow, et.al. titled "Intersection Crossing Based on a Pedestrian Time Gap. The authors described an intersection where one approach had a vertical crest which reduced the visibility distance for pedestrians crossing the street. The pedestrian crossing time was estimated at 12.6 seconds using 3.5 feet/sec. This is considerably longer than the time for a vehicle to cross the intersection.
No mention was made as to whether the vehicles arrived uniformly or randomly or whether it was even determined. The volume on the problem-approach was 408 vph. If the vehicles were randomly distributed, the probability of a gap >12.6 seconds is only 0.24.
It was not clear what kind of intersection treatment was used, if any at all. In the full report, available from the web site, various treatments were described. I am wondering if a treatment was selected, used, and what was the resulting performance given the low probability of acceptable 12.6 sec. pedestrian gaps occurring.
Samuel C. Tignor