Web Extra: Risky Business

By Steven A. Bloch

Choosing to change risky driving behaviors could reduce the amount of carnage on our highways

Life is fraught with risk—from natural disasters and crime to simple accidents at home. Most of us worry about these things, at least sometimes. But in most people's daily life, driving is unquestionably the riskiest activity.

The chance that you'll die or be seriously injured in a car crash on any given day is, of course, small. But that risk adds up over the years. For Americans ages 4–34, car crashes are the leading cause of death. Think about that: the leading cause. Your lifetime risk of being killed in a motor vehicle crash is one in 88, three times greater than being the victim of a homicide—and more than 50 times greater than dying in an airplane crash.

For all Americans, car crashes are by far the leading cause of "accidental" death. About 43,000 people are killed and 2.5 million people suffer disabling injuries every year in about 6 million car crashes.

But the fact is most crashes aren't accidents. They could have been prevented. You can't control the way other motorists drive, but you can lower the chances that you'll be involved in a car crash by avoiding certain types of high-risk driving behavior.

Quantifying risk

What counts as risky driving behavior? Certainly, drunk driving—about 40% of collisions that result in death are alcohol-related. But apart from that, speeding, drowsy driving, distracted driving and aggressive driving are commonly viewed as being among the most dangerous.

Several years ago, the AAA Foundation for Traffic Safety commissioned the Virginia Tech Transportation Institute (VTTI) to conduct an innovative study of risky driving behaviors. At the end of 2006, VTTI produced a report, How Risky Is It? An Assessment of the Relative Risk of Engaging in Potentially Unsafe Driving Behaviors. Because the study used in-vehicle cameras that examined actual driving behavior, for the first time it was possible to compare what drivers did immediately before a crash or near-crash. Based on the VTTI report and related studies, here's what we know about the risks associated with some of our most dangerous driving behaviors.

Speeding

Speeding nearly triples the risk of being involved in a crash or near-crash. Driving too fast for existing driving conditions reduces your ability to steer safely, extends your stopping distance, and can prevent you from reacting quickly enough to avoid a crash.

Relatively small speed increases can have large and possibly lethal consequences because a vehicle's crash impact increases exponentially with its speed. For example, driving 55 mph versus 50 mph increases a car's crash impact by 21%. Driving 60 mph versus 50 mph increases impact by 44%. Speeding is probably the single biggest cause of traffic fatalities, according to a 2004 Institute of Transport Economics report that reviewed 97 different studies of the subject. The report also concluded that a 10% reduction in average traffic speed would likely reduce fatal traffic crashes by 34%.

Drowsy driving

Drowsy driving also nearly triples the risk of being involved in a crash or near-crash. About half of all adult American drivers surveyed admit to sometimes driving while drowsy, according to a 2002 National Sleep Foundation poll. What's more, 37% of drivers admitted to having fallen asleep at least once while driving, according to a recent Gallup poll sponsored by the National Highway Traffic Safety Administration. And 51% of teens reported driving while drowsy within the previous year, a 2006 NSF poll found.

With numbers like these, it's not surprising that a recent analysis of U.S. data showed that 4% of police-reported crashes involved drowsiness or falling asleep at the wheel. The actual number of crashes caused by drowsy drivers is probably much higher, because drowsiness is easy for police to overlook as a cause. In the United Kingdom, studies indicate that fatigue is a factor in more than 15% of collisions.

Distracted driving

Distracted or inattentive driving nearly doubles the risk of being involved in a crash or near-crash. In some cases, drivers are completely unaware of important risks; in others, their reaction times are dangerously delayed.

A 2003 AAA Foundation study found that almost all of the participants engaged in distracting activities while driving. Of the hours of driving that researchers observed, drivers were distracted nearly one-third of the time that vehicles were in motion. Conversing with passengers was the most distracting activity, eating and drinking was second and reaching for objects or vehicle controls was third.

Various studies have shown how dangerous distracted driving can be. The most recent, a 2006 NHTSA-funded study of 100 vehicles outfitted with video monitors, found that engaging in nondriving tasks and not watching the road carefully contributed to far more crashes than previously believed—78% of crashes and 65% of near-crashes.

Of course, some distractions are more perilous than others. For example, the 2006 NHTSA study also showed that cell phones and PDAs were by far the most frequent contributor to dangerous events, followed by passenger-related inattention; internal distractions, such as moving objects around; vehicle-related factors, such as fussing with radios and vehicle controls; personal hygiene and eating.

Aggressive driving

Aggressive driving more than doubles the risk of being involved in a crash or near-crash. It can be hard to define, but drivers know it when they see it—rude gestures, verbal abuse, flashing headlights out of annoyance, aggressive tailgating, driving at excessive speeds, unsafe lane changes or deliberately blocking other drivers from changing lanes.

Because aggressive driving is difficult to define, there are few estimates of the number of crashes it causes, and the available estimates we do have are problematic. Representatives from the NHTSA once testified that perhaps two-thirds of all highway deaths were related to aggressive driving. Traffic-safety researchers, however, have been reluctant to set precise percentages.

Surveys of drivers suggest that the aggressive driving problem is widespread and perhaps growing. A recent poll found that 60% of drivers saw unsafe driving by others as a major threat—even though more than half admitted to occasionally driving aggressively themselves.

And sometimes, people don't see that they're part of the problem. A British survey found that, while 62% of respondents reported having been tailgated aggressively, only 6% admitted to aggressive tailgating themselves.

The bottom line

Risk is part of life. But, for most of us, driving is the most dangerous regular activity, so it's good to know that we can control a lot of our risk in that arena—and increase our odds of getting to our destination safely. We can decide, for example, to cut our crash risk in half by driving less aggressively or driving with our mind focused fully on the road. Similarly, we can consider whether it's really worth tripling our risk of a crash by speeding, or driving while drowsy.

Some people believe that, one day, car crashes will become almost a thing of the past, as auto manufacturers and highway engineers develop better technology. But those days are a ways off. In the meantime, we can start thinking about whether we really need to answer that phone call, or take a bite out of that cheeseburger precariously perched on the passenger seat. After all, that cell phone call might just be a wrong number. And the cheeseburger might still be juicy when we get home—or at least when we get to the next red light.

Steven A. Bloch has been a traffic-safety researcher and policy analyst with AAA for 25 years.

How Risky Is It? An Assessment of the Relative Risk of Engaging in Potentially Unsafe Driving Behaviors is available for downloading at www.aaafoundation.org. .