Traffic signals allowing pedestrians to cross an intersection several seconds before oncoming cars reduce conflicts between pedestrians and turning vehicles as well as the incidence of pedestrians yielding the right-of-way to turning vehicles. These are the principal findings of a new Institute study.

Providing pedestrians a three-second head start through the use of a leading pedestrian interval a signal that allows pedestrians to begin crossing prior to the release of turning vehicles was studied at three intersections in St. Petersburg, Florida. Researchers recorded the number of conflicts between pedestrians and turning vehicles and the number of times a pedestrian yielded to a turning vehicle both before and after leading pedestrian intervals were installed. Conflicts were defined as any situation in which the driver engaged in abrupt braking or either the driver or pedestrian took sudden evasive action to avoid a collision.

After leading pedestrian interval signals were installed, conflicts were nearly nonexistent. The odds of a conflict for pedestrians leaving the curb during the beginning of the walk period were reduced by about 95 percent, from 2.8 to 0.2 per 100 pedestrians. The likelihood of a pedestrian yielding to a turning vehicle decreased by about 60 percent.

"Leading intervals provide pedestrians early access to crosswalks, giving them an advantage over motor vehicles in competition to occupy an intersection," says Richard A. Retting, the Institute's senior transportation engineer. "So intervals are an inexpensive means to intervene on behalf of pedestrians."

He adds that while past research has shown warning signs and pavement markings also reduce conflicts between pedestrians and cars, such devices do so by raising a pedestrian's awareness of potential threats from turning vehicles (see Status Report, Vol. 31, No. 7, Aug. 10, 1996).