by Joseph D. Younger
In a world where people do all kinds of crazy stuff in a car besides driving, Dr. Sheila Klauer has seen it all.
She has witnessed a woman attempting to insert her contact lenses while speeding down an urban expressway.
She watched a driver eat Chinese carryout from a carton—using chopsticks. And she saw a teenage boy change his clothes while behind the wheel in moving traffic.
How risky is such behavior?
What are the odds that such activities will lead to a crash?
Klauer, a senior research associate at the Virginia Tech Transportation Institute, recently led a research team sponsored by the AAA Foundation for Traffic Safety that asked—and answered—those questions.
The Ground Rules
More than 240 participants in and around Washington, D.C., agreed to have their everyday driving behavior recorded for a year. They drove vehicles outfitted with five digital video cameras and a “black box” that registered following distance and lateral acceleration as well as speed, forward acceleration, braking and other data.
The study recorded 82 collisions, 761 near-crashes and over 8,000 “incidents”—circumstances that required quick action to avoid a crash.
“For the first time, we could look at exactly what a driver was doing immediately before a crash or near-crash,” explains Klauer.
After viewing videos and crunching numbers, researchers identified four specific behaviors that dramatically increase the odds of having a crash: speeding, drowsy driving, taking your eyes off the road for two seconds or longer and “aggressive driving”—a combination of tailgating, speeding, frequent lane changes, and other maneuvers that reveal a driver’s impatience, anger or frustration.
Researchers found that drowsiness contributes to far more traffic crashes than anyone suspected.
Speed
Speeding nearly tripled the crash odds. By “speeding,” researchers don’t mean simply exceeding posted limits. They really mean driving faster than prevailing traffic or driving at a speed “inappropriate” for conditions.
Drowsiness
Drowsiness proved as dangerous as speeding, also nearly tripling the crash odds. Drowsy driving as a cause of crashes surprised even the researchers.
“In our study, it accounted for a much higher percentage of crashes than in any previous study,” notes Klauer. Up until now, best estimates suggested drowsiness causes about 100,000 crashes a year—roughly 2 percent to 4 percent of all collisions nationwide. The Foundation-sponsored analysis, however, puts the number closer to 20 percent.
Why the big difference?
Previous estimates relied on police reports and after-the-fact attributions of causes. By contrast, AAA Foundation-sponsored researchers looked at real-world videos of actual drivers in the minutes immediately preceding a crash or near-crash, and they found lots of signs of sleepiness: yawning, slack facial musculature, and drooping eyelids.
A lack of eye movement characterized drowsy drivers. They tended to stare fixedly, through partially closed eyes. Almost equally surprising, most drowsy-driving episodes occurred during broad-daylight hours.
Distractions
Distractions requiring the driver to look away from the road for two seconds or longer nearly doubled the chances of a crash. This included applying make-up, dialing a cell phone, searching for a CD, or reading behind the wheel—all non-driving-related activities. Adjusting climate controls, changing radio stations and other behaviors associated with driving usually didn’t take more than two seconds.
The results show how quickly and unexpectedly traffic conditions can change, making distractions dangerous even maintaining a “safe” following distance.
“A lot of the rear-end crashes in our study occurred when our drivers kept a greater-than-two-second headway between their car and the car ahead of them,” Klauer says.
Despite this safety cushion, they turned their attention away from the road, something happened that caused traffic to slow down or brake, and—bam!—they hit the vehicle ahead.
Aggression
Aggressive driving, like two-second distractions, also doubled the risk of a crash. Researchers defined “aggressive driving” as using the vehicle to menace another driver or pedestrian, and also as a combination of speeding, weaving in and out of traffic, running stop signs, and other actions.
Not Just Tailgating
Tailgating alone did not constitute aggressive driving, and it didn’t necessarily lead to more crashes or near-crashes.
In fact, researchers found tailgating common in congested urban areas like Washington, D.C.; drivers simply adapt to prevailing conditions and manage to reduce their following distance without too much trouble. “While following too closely should not be advocated as a safe driving behavior,” concluded researchers, “drivers learning to be more alert and responsive to [congested] dynamic traffic environments may have contributed to [the low crash rate].”
Future Studies
Klauer and her colleagues hope to mine this rich vein of unique, real-world data further.
Future studies might examine crash risk associated with particular types of drivers or combinations of activities. Videos and black-box readings may prove useful in developing collision avoidance systems.
“For example, we might look at which types of collisions could’ve been prevented with a warning system,” notes Klauer.
Until then, research delivers an unambiguous message: distractions and drowsiness are far more dangerous than anyone had believed.
As Klauer puts it, “It has certainly taught me the importance of staying alert and keeping your eyes on the road at all times.” |
