Perhaps you've heard the claim that talking on the phone while driving is as risky as driving drunk. Indeed, a driving simulator study found "profound" impairments in both cellphone chatters and in people with a blood alcohol level of 0.08.
But here's the surprising thing: It doesn't seem to make a difference whether drivers are using hand-held phones or hands-free systems. What matters is simply that they are talking with someone outside the car.
Everyone understands the risk of taking your eyes off the road or your hands off the steering wheel, says David Teater, senior director of transportation strategic initiatives for the National Safety Council. But most people don't appreciate the demands of driving on the parts of your brain involved in attention, planning and language, Teater says. Talking on the phone uses some of the same brain space that driving does. So if you're trying to do both, at least one of them is going to suffer.
It's a problem of dual tasks, says David Strayer, a cognitive scientist at the University of Utah. Some dual tasks are no problem, such as walking and chewing gum at the same time. Others are trickier, such as patting your head and rubbing your belly.
A recent study demonstrates that driving while conversing falls squarely in that tricky category. Researchers measured reaction times in young adult drivers exposed to a variety of traffic situations in a driving simulator. Talking on a hand-held cellphone slowed drivers' reactions to seeing a pedestrian enter a crosswalk by 40 percent compared with no conversation. The effect was identical for drivers who talked on a hands-free phone.
How do other distractions compare? Here's the research on some common car activities (besides driving):
- Is talking on the phone more distracting than listening to an audiobook?