The Scientific Odds That Using a Cell Phone Will Make You a Bad Driver

Some impressively specific data.

Image
Shutterstock

Common sense suggests that any activity that pulls your eyes away the road will impair your ability to see what's coming from the driver's seat. If you're looking up a phone number in your smart phone, you can't look at the car in front of you. If you're peering down into the fast food bag wedged between your legs, you're probably not simultaneously scoping out your rear-view mirror.

So it probably won't surprise you to learn that even people who are experienced drivers are more likely to crash while dialing a cell phone. Here, though, are some awfully specific risk ratios: An experienced driver doing this is about two-and-a-half times more likely to get in a crash or have a near-miss than if they weren't fumbling with a phone at all. And the crash risk for novice drivers goes up more than eight-fold. Just reaching for a phone makes a novice driver seven times more likely to have a crash or close call.

These figures come from a new study just published by the New England Journal of Medicine. The results are particularly fascinating for how the researchers came up with them: The study recruited 42 freshly minted drivers in southwestern Virginia, and 109 more seasoned drivers in the Washington, D.C., area, who had, on average, 20 years of experience driving. The researchers outfitted their cars with a host of devices: GPS systems, sensors, cameras pointing toward the driver and outward at the road. All of this technology then continuously recorded what happened next, over a full year for the novices and 18 months for the other drivers.

"What’s remarkable about it is it allows you to objectively identify risks for a cash," says Bruce Simons-Morton, one of the co-authors and an investigator with the Eunice Kennedy Shriver National Institute of Child Health and Human Development. "That's because virtually every crash or near miss is associated with an elevated gravitational force." 

This occurs when a car suddenly stops or swerves. And these moments can be detected by an accelerometer placed in the car. Over the course of the study, these people got into 685 crashes or near misses (167 of them among the youngsters).

Thanks to all the technology, scientists have objective data about such risky events (a car suddenly swerved), the driver's culpability (the forward-facing camera records what the driver sees), and the activity that may have led to it (the in-cab camera can capture burritos mid-bite or teenagers diving for an iPhone).

The young drivers, who were recruited within three weeks of earning their driver's license, turn out to be tripped up by all kinds of "secondary" activities in the driver's seat. They're three times more likely to get in a crash when they're eating, and four times more likely when they're looking at roadside objects. They're eight times more likely to get into trouble when reaching for an object other than a cell phone.

Experienced drivers, on the other hand, were only handicapped by one activity: dialing a phone. Talking on it or reaching for it didn't hamper them. Talking by itself also didn't drive up the risk for the younger drivers, as many people suspect. This may be because talking requires some cognitive demand, Simons-Morton says, but it doesn't take our eyes off the road. And all of the activities that increased risk in this study did just that.

The findings suggest, among other things, that those of us who've been driving for a while are pretty good at multitasking.

Simons-Morton puts it a little differently: "I think what it means is that when you’re inexperienced, you’re not very good at multitasking, and you’re not very good at determining when, under what driving conditions, to engage in these tasks."

Previous research also suggests that experienced drivers simply have a harder time taking their eyes off the road (which is a good thing).

"Some cognitive psychologists say there is no such thing as dividing one's attention," Simons-Morton says. "You’re either attending this or you're attending that. But it is the case that experienced drivers tend to be uncomfortable when their eyes are off the road, and they tend to look back."

Top image: George Fairbairn/Shutterstock.com

About the Author

  • Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific StandardGOODThe Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.