In Brief

Who hasn't been startled, while driving home at night, to find one's headlights flash across a neighbor walking his dog or jogging in the dark? Though your neighbor may have seen you coming from blocks away, to you he was virtually invisible until you drove dangerously close.

"Pedestrians overestimate their night time visibility," said Michael Sivak, PhD, director of the University of Michigan Transportation Research Institute's Human Factors Division. "They argue to themselves that if they can see the oncoming car, surely the driver with those very bright headlights is able to see them as well."

Not always true, as evidenced by the fact that each year nearly 5,000 U.S. pedestrians are hit and killed by vehicles, according to the National Highway Traffic Safety Administration. In fact, pedestrians are three to four times more likely to die at night than during the day. Researchers have found that poor visibility and low contrast are often cited as causal factors in these fatal accidents.

The good news is that psychologists' insights into the brain's visual systems can help prevent such pedestrian deaths, said speakers during a session on traffic safety at APA's 2007 Annual Convention.

One solution is to take advantage of humans' ability to recognize biological motion, said speaker Stacy Balk, a human factors doctoral student at Clemson University. She reported that applying 11 pieces of retroreflective material to pedestrians' major joints allows drivers to recognize them from 80 meters away. However, the general public has yet to embrace this safety measure-perhaps because the full, 11-element treatment may be too cumbersome and impractical for regular use, said Balk.

As an alternative, Balk found that pedestrians who wore retroreflective material on only their ankles and wrists were conspicuous to drivers at 50 meters, versus about 15 meters for pedestrians with a single retroreflective rectangle on their torsos. In another study, she found that pedestrians who wore retroreflective material on their ankles in addition to an ANSI Class II safety vest-the industry standard for construction and road workers-increased their conspicuity to the same level as someone wearing the most effective, 11-piece biomotion suit. With these configurations, she also found a conspicuity advantage when pedestrians stood still in addition to when they walked.

Keeping pedestrians-particularly "professional pedestrians" such as highway workers and law enforcement officers-safe at night can be as easy as adding a few strips of retroreflective material to one's ankles.

"It's really simple, it's cheap and effective," she said.


--E. Packard