Motorists who try to “beat the light” by speeding through intersections when the traffic signal turns yellow cause hundreds of deaths each year, a new study has found.
Oregon State University researchers said the finding spotlights the need to improve yellow-light timing and establish clearer boundaries for what engineers call the traffic “twilight zone” -- that area before a stoplight intersection where drivers must decide whether to stop or go when the traffic light turns yellow.
"There are more than 30,000 traffic fatalities each year in the U.S., and about 2,000 of them occur in stoplight intersections," said researcher David Hurwitz, an OSU transportation engineer. "We think those crashes can be reduced with a better understanding of exactly where the dilemma zone is and how traffic lights and other technology can be adjusted to help manage it."
To identify factors that might reduce risks at intersections, OSU researchers studied the variables involved in stoplight accidents -- including speed and location of oncoming traffic, yellow-light timing and how drivers make split-second decisions on the road.
In one recent study, researchers examined what goes into the "fuzzy logic" drivers use when deciding when – and whether – to stop for a yellow light. A driver who is some distance away usually stops for a yellow light; one who is close to the intersection will go ahead.
OSU engineers concluded establishing a clearer “boundary definition” – so drivers know when to stop and when to go, depending on how close they are to the intersection when a stoplight turns yellow – would improve road safety.
The findings were published in two recent studies, in research that was supported by the Vermont Agency of Transportation and the Lilo and Richard Smith Transportation Fellowship.
"We want to help drivers know whether to stop or proceed, and do it in a manner that is safe," Hurwitz said. "This approach should help accomplish that, prevent accidents and save lives."