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Flying circus of physics

Racing over a rail crossing

Sunday, March 01, 2015

Racing over a rail crossing
Jearl Walker
March 2015 

Why do people drive vehicles over a rail crossing (where a road passes over train tracks) even when they are being actively warned of an approaching train? Here are a few examples: Amtrak collision with car many cars and then a bike Note that the driver of the care with the video camera was attempting to pull to the left around the barrier that had been lowered to stop cars. truck dodging gates

This question was addressed by H. W. Leibowitz in a 1985 paper in the American Scientist. Part of the problem is the basic safety design at the crossing. The warnings must begin such that a collision can be avoided for the fastest train, the slowest car, and the worst weather. That means that a motorist who obeys the warning and stops might be waiting a long time when a slow train is actually coming. With experience of long delays before trains even show up, a motorist might choose to drive over the crossing. Of course, getting away with that a few times can lead to a habit of ignoring the warnings.

This might explain the behavior of a motorist near the crossing but how about those more distant motorists who can see the train approaching the crossing and then attempt to beat the train there. Leibowitz argued that the size of the train creates an illusion about the train’s speed. After years of driving, motorists can estimate the speed of another car approaching an intersection along a perpendicular road. But a train is much larger than a car. That larger size results in a perceived slower speed, thus giving the possible illusion that the motorist might beat the train to the crossing. Leibowitz suggested how we might see this speed illusion in a more common setting: When you are at an airport and can watch airplanes land, note that the very large airplanes appear to land at noticeably slower speeds than smaller airplanes. However, the landing speeds are actually all about the same.

More videos test with log carrying truck test with steel coil on truck parade float flatbed truck statistics rail idiots man runs in front of second train

Dots · through ··· indicate level of difficulty
Journal reference style: author, title, journal, volume, pages (date)
·· Schiff, W., “Perception of impending collision: A study of visually directed avoidant behavior,” Psychological Monographs: General and Applied, 79, No. 11, (26 pages) Whole No. 604 (1965)
· Leibowitz, H. W., “Grade crossing accidents and human factors engineering,” American Scientist, 73, 558-562 (November-December 1985)
· Clark, H. E., J. A. Perrone, and R. B. Isler, “An illusory size-speed bias and railway crossing collisions,” Accident Analysis and Prevention, 55, 226-231 (2013)

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