A small 2008 study showed that when people listened to an audiobook (in this case, "Dracula"), their performance was the same as when they drove without distraction. But when they carried on a phone conversation with one of the researchers (about hobbies and weekend activities), their performance worsened.
- How distracting is radio?
Strayer partnered with the American Automobile Association to try to measure the relative strength of various cognitive distractions on driving. Study subjects were tested in a driving simulator or a real car while listening to the radio or a book on tape. On a scale of 1 (no distraction) to 5, radio measured 1.2 and the audiobook measured 1.75. The distraction that rated a 5 was to have drivers try to solve math problems and remember a series of words.
- Is talking on the phone more distracting than talking to a passenger?
The cognitive workload for the driver is the same, according to Strayer. In his test, conversing with a passenger rated a 2.3 on the 1-to-5 scale; talking on a hand-held phone, a 2.4; and a hands-free phone, a 2.3. However, having another person in the car generally results in safer driving, because there's often an extra set of eyes on the road. Also, passengers tend to stop talking when the demands of driving increase, Strayer says. "So passenger and cell conversations have different crash risks because the passenger helps out."
Note: Teen passengers don't have the same helpful effect with teen drivers.
- Are there apps for that?
There are apps that when enabled — or when you're traveling over, say, 10 mph — automatically answer calls (and texts) and apps that will read your text messages or e-mails aloud to you. One recent study found that listening to (but not answering) a ringing phone while driving was a distraction.
Despite the data, there's no indication that people are giving up their phone conversations. There are probably plenty of reasons for that, but it's hard to tackle a lack of self-awareness — or worse, hubris. "People notice others driving erratically and talking on their phones, but they don't notice themselves making similar driver errors," Strayer says.
In the past, people would brag about being good drivers even when drunk, Teater says. The same thing is happening now with cellphones. Teater's work was spurred by the death of his 12-year-old son in a cellphone-related car accident. "You never think it will happen to you — until it does," he says.