Cell phones distract drivers, hands down

Calling all motorists: Using a hands-free cell phone while driving markedly interferes with the ability to maneuver a vehicle safely, according to several new tests.

In 2001, David L. Strayer of the University of Utah in Salt Lake City and his colleagues reported that people talking on either handheld or handsfree cell phones during simulated drives ran red lights more often and reacted more slowly to traffic signals than when not talking on a phone. No such problems occurred for drivers who either talked with a passenger or listened to the radio or to books on tape.

In new investigations led by Strayer, 110 college students operating a driving simulator caused more rear-end collisions and reacted more slowly to vehicles braking in front of them during periods when they talked on a hands free cell phone. The worst impairments occurred while driving in heavy traffic, the researchers report in the March Journal of Experimental Psychology: Applied.

Cell-phone conversations sapped the attention required to discern important driving cues, Strayer holds. For instance, immediately after taking simulated drives past a series of billboards, volunteers could recall fewer of the signs if they had been talking on a handsfree cell phone. Yet eye-tracking tests showed that drivers looked directly at two-thirds of the billboards, whether or not they used a cell phone.

In another test, volunteers used a joystick to align a cursor with a moving target on a computer screen. At the same time, a series of words flashed briefly on the screen.

Participants later recognized fewer of those words if they had been talking on a hands-free cell phone during the exercise.

Strayer’s prescription: Don’t drive while yapping on the phone.


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Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.