CORVALLIS, Ore. Hundreds of lives are being lost each year in the United States because of mistakes made in what engineers call the "dilemma zone" that area before a stoplight intersection where the traffic light turns yellow and the driver isn't sure whether to stop or go ahead.
New research at Oregon State University will help to more precisely identify that danger zone. Traffic engineers can then use than information, along with advanced technology that can monitor the speed and location of oncoming traffic, to improve yellow-light timing and help address this problem.
When more widely implemented, this approach should help reduce driver confusion, add certainty to how intersections should be managed, and save lives.
"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 David Hurwitz, an OSU assistant professor of transportation engineering. "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."
Factors that lead to the problems in the dilemma zone include driving speed, distance to the stop light, driver skills, laws that vary by state, occasional scofflaws who are trying to "beat the red light," and simple confusion by drivers who want to do the right thing but aren't sure what it is.
There are many variables involved, Hurwitz said, such as vehicle speed and position. To help address that, researchers in one recent study used a tool called "fuzzy logic." This provides a way to produce more exact decisions with inexact data, which in this case can include everything from drivers with very different skill sets and reaction times to automobile speeds and road variability.
Based on their speed and proximity to an intersection, when the traffic light turns yellow a driver has to make a decision wheth
|Contact: David Hurwitz|
Oregon State University