Cell phones impair driving in similar way to age

A new University of Utah study has found that when young drivers are talking on cell phones they drive like older drivers -- they move and react more slowly and are at increased risk for accidents.

"If you put a 20-year-old driver behind the wheel with a cell phone, their reaction times are the same as a 70-year-old driver who is not using a cell phone. It's like instantly aging a large number of drivers," says David Strayer, a University of Utah psychology professor and lead author of the study.

The study by Strayer and Drews was published in a recent issue of the journal Human Factors, published by the Human Factors and Ergonomics Society.

When 18- to 25- year olds used a driving simulator while talking on a cell phone, their reaction time to brake lights on a car in front of them was similar to 65- to -74 year olds who were not on the phone.

The elderly drivers became even slower when speaking on a cellular phone. However, their driving ability was not as bad as earlier studies had predicted.

Regardless of age, drivers who talked on cell phones were 18 percent slower in hitting their brakes than drivers who did not use phones. However, they also had a 12 percent higher following distance, and took 17 percent longer to regain their speed after braking.

In addition, "there was also a twofold increase in the number of [simulated] rear-end collisions when drivers were conversing on cell phones," the study says.

This comes on the heels of studies conducted by Strayer and his colleagues in 2001 and 2003 showing that hands-free cell phones distract drivers just as much as hand-held phones. Additional studies have shown that drivers using cell phones are more impaired than drunk drivers with a blood alcohol level above 0.08.

Each participant had normal vision and a valid drivers license. They used a high fidelity driving simulation during which a car in front of them would brake at periodic intervals, for a total of 32 times. They drove four simulated freeway trips lasting about 10 minutes each. During half of the trips, they talked on a hands-free cell phone with a research assistant.

The simulator measured driving speed, following distance, reaction time and time to regain speed. Those factors "have been shown to affect the likelihood and severity of rear-end collisions," Strayer and Drews wrote.

"Older drivers were slightly less likely to get into accidents than younger drivers," Strayer says. "Why? They tend to have a greater following distance. Their reactions are impaired, but they are driving so cautiously they were less likely to smash into somebody," although in real life, "older drivers are significantly more likely to be rear-ended" because of their slow speed.

When combined with earlier studies, they found 12 cases in which the driver collided with the car in front of them. In 10 of those cases the driver was using a cell phone. That provides "clear evidence that drivers using a cell phone were more likely to be involved in a collision than when these same drivers were not using a cell phone," the psychologists concluded.

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