The numbers make you wonder: How do drivers get anywhere at all without bashing into one another? Distractions take up at least 16 percent of the time we spend behind the wheel.

To put it another way, we're doing something completely unrelated to driving for one minute out of every six on the road. We're fiddling with the radio. We're sipping a cup of coffee or munching a burger. We're soothing an infant or disciplining toddlers. We're combing our hair. Maybe we're even reading the morning paper or jotting down notes for a meeting.

And that includes just purely physical activity. It doesn't take into account distracting conversations we might have with passengers. Add in talking, and we drive with divided attention more than 30 percent of the time.

Those startling statistics come from recent research conducted at the University of North Carolina Highway Safety Research Center and sponsored by the AAA Foundation for Traffic Safety. Part of an ongoing, multi-phase inquiry into distracted driving, the study videotaped volunteers during everyday driving, analyzed their actions behind the wheel and explored the safety consequences.

For years, safety experts have known that multi-tasking spells trouble. The National Highway Traffic Safety Administration (NHTSA) estimates that inattention or distractions cause up to 30 percent of all highway crashes-as many as 1.2 million per year. But the AAA Foundation's newest study is the first to examine what we really do when we're supposed to be driving, and the results show that we've become a nation of multi-taskers. How do distractions affect our driving performance? And how can we better manage our multi-tasking without compromising safety?

Tale of the Tape

In the foundation's one-of-a-kind research, 70 volunteers agreed to have video cameras installed in their vehicles to record up to 10 hours of their driving. Knowing only that they were participating in a study of "how traffic and roadway conditions affect driving behavior," they went about their normal routines. Then, sampling the tapes in half-hour segments, researchers watched more than 200 hours of everyday driving, cataloged the drivers' actions, noted road and weather conditions and analyzed the consequences.

The slices of life revealed that nobody paid full attention all of the time. Everyone did something unrelated to driving, such as eating, smoking, grooming, reading or writing. Three out of four subjects spent time talking with other passengers, and 85 percent gawked, rubbernecked or otherwise paid attention to something outside the vehicle.

Excluding conversations with other passengers, potentially distracting physical activity accounted for 16 percent of the total driving time while the vehicle was moving (see "What We Do While We Drive," page 12). Reaching and leaning for wallets, purses, tollbooth change, maps and other objects occurred most frequently; eating and drinking occupied the most time.

First, the Good News

After analyzing all this nondriving activity, researchers found at least a bit of reassuring news. Drivers seem to know that some distractions are dangerous and try to manage them. "We found that people do adjust their behavior to a certain extent," says Peter Kissinger, AAA Foundation president. "They have a tendency to do potentially distracting things while their cars are stopped." For instance, 70 percent of the reading and writing, 34 percent of grooming and 25 percent of the cell phone calls took place while the vehicle was stopped. (Volunteers came from a Philadelphia suburb and Chapel Hill, N.C., where drivers could legally use their hand-held phones while driving.)

A closer look at the data shows that people may learn better time management as they age. "When we looked at older drivers, we found that they didn't engage in most of these activities as often as younger drivers," notes Dr. Jane Stutts, manager of epidemiological studies at the University of North Carolina Highway Safety Research Center and the study's principal investigator.

In fact, drivers age 60 and older ranked last among other age groups in nearly every category of distraction except conversations. By contrast, 18- to 29-year-olds showed no qualms about multi-tasking; they ate and drank, read and wrote, and adjusted the sound system more than any other age group. In fairness, however, middle-age drivers led the way in cell phone conversations and personal grooming.

Gauging Danger

Obviously, various distractions-even various activities within the same category -may differ wildly in their effects on driving performance. For example, eating a lollipop requires far less concentration than eating a sloppy, overstuffed burrito. Consequently, you would expect lollipops to affect driving performance less than burritos. "We could only code each distraction as 'yes' or 'no,'" explains Stutts. "Determining where it fell on the continuum of danger would have introduced a whole new layer of subjectivity in the research. In other words, we couldn't just note that the driver reached for something. We would have to judge where he reached or how far back he reached, and that would have been too difficult to do objectively."

Instead, to measure the consequences of multi-tasking, researchers relied on "observable outcomes"-taking both hands off the steering wheel, for example, or wandering within a lane, swerving into another lane, or braking suddenly.

In this analysis, reaching for objects inside the vehicle seems to pose the greatest risk. It resulted in a significantly higher incidence of swerving, encroaching on another lane and sudden braking. Smoking, on the other hand, posed the least risk. In fact, so-called adverse vehicle events actually declined after drivers lit up-perhaps because smoking had a calming effect.

Perilous Coincidences

Of course, distractions become really dangerous when they coincide with some other event-a child stepping off the curb, for instance, or the truck in front of you stopping suddenly. Thankfully, researchers captured no such crashes on video during the course of the study. But the sheer number of distractions and the time spent multi-tasking raises some serious safety concerns.

"You just never know when you'll have to focus your full attention on the road to avoid a collision," notes Fairley Washington, acting director of communications for the AAA Foundation. "Raising the number of distractions raises the odds that you'll be distracted in a dangerous situation."

Furthermore, all this multi-tasking inspires overconfidence. Because we allow ourselves to deal with so many distractions so often, we think we can get away with multi-tasking forever. "People constantly delude themselves about their abilities behind the wheel," notes Washington. "They think they're doing great-until they have a crash."

What Lies Beneath

Yet there's a more ominous problem lurking below all the statistics-one that Stutts hints at when discussing the limitations of her team's research.

"We could only catalog the distractions that could be captured on videotape," she explains. "For example, we could tell when drivers had their eyes on the road. But we couldn't tell whether they were paying attention to what they were seeing."

Stutts cites cell phone conversations as a perfect case in point. In the Foundation's study, for example, cell phone conversations had little apparent effect on real-world driving performance. Drivers could talk, keep their eyes on the road and at least one hand on the wheel, and stay in their lane. However, she is also quick to point out that other research in more controlled environments indicates that cell phone conversations present a far more serious cognitive distraction than a mere videotape would suggest.

In other words, studies such as this measure just the tip of an enormous iceberg. The space between your ears contains a wide, wide world of potentially deadly distractions-daydreaming, wandering attention and simply "zoning out." Until scientists invent a way to videotape your thoughts behind the wheel, such cognitive activity remains terra incognito. As Stutts and her colleagues concluded, "We were unable to capture any measure of cognitive distraction, which the literature suggests may pose the greatest risk to driving safety."

Managing Multi-Tasking

In the meantime, what are we supposed to do? Ban makeup and hair care products inside cars? Outlaw messy sandwiches behind the wheel? Eliminate coffee to go? Then what would we do with all those cupholders?

According to Stutts, managing multi-tasking, like any safety concern, starts with education. "Education isn't very well respected as an answer to safety problems these days," she says, "but I think there's something to be said for raising the general climate of awareness about distracted driving. When the public raises its consciousness about distracted driving, it could become less socially acceptable, in the same way that drunk driving and riding without a safety belt have become unacceptable."

Parents, for example, could warn their teenage sons and daughters that fishing for a dropped CD, no less than talking on a cell phone behind the wheel, can lead to a collision.

Adults can train themselves to manage multi-tasking better, too. Why root around in your pocket or purse when you could count out exact change for a tollbooth before you get behind the wheel? Why decipher the tiny type on a detailed map when you can write out directions in big letters and tape them to the dash beforehand?

Such common-sense approaches may seem like little things. But, as research on multi-tasking shows, attending to little things at the wrong time can add up to big crashes on the road.