Preventing driving accidents involving teenagers

Behavioral strategies parents can use to reduce their children's risk of injury or death.

Motor vehicle accidents remain the leading cause of death for teenagers, accounting for nearly 41% of fatalities in 2004 among young people ages 13 to 19. This deadly toll results, to a large extent, from lack of driving experience, but it also reflects the fact that the teenage brain is still a work in progress. The prefrontal cortex, which contains the neural mechanisms of self-control, is one of the last parts of the brain to mature. As a result, teenagers are prone to risk taking, impulsive behavior, and sensation seeking — all of which can cause trouble behind the wheel of a two- or three-ton vehicle hurtling down a highway.

One possible solution is to increase the age requirement for driver's licenses to 17 or 18. But there is no consensus that this will reduce crash rates.

The Institute of Medicine convened a panel of experts to identify behavioral and cognitive strategies to prevent motor vehicle accidents involving teenagers. Their findings were summarized in a special issue of the American Journal of Preventive Medicine published in September 2008. Some helpful tips for parents follow.

Don't count on driver's ed

Although driver's education courses may be marketed for their safety, there is no proof that they reduce the rate of motor vehicle accidents involving teenagers. In fact, specialized classes that emphasize practice in skid control and other emergency maneuvers may actually increase risk of crashes, especially for young men, possibly because of excess confidence or a desire to "show off" skills for friends.

Accumulating more hours of parent-supervised driving may not help either. Studies have found that teenagers whose parents spend a lot of time supervising their driving are no more likely than teenagers with less supervised driving to avoid motor vehicle crashes once licensed. It's not clear why, but parents may be restricting practice time to relatively safe conditions, such as driving during the day on a side road, rather than exposing novice drivers to more complicated situations, such as driving at night or in snow. Parents may also inadvertently act as co-drivers, by helping to watch for other cars and checking "blind spots"; as a result, teenagers may not acquire the skills they need to drive by themselves.

The research conclusively shows that only by driving alone do teenagers develop the complex skills they need to be safe on the road.

Monitor behavior, not the trip

Many parents set limits on car trips, by asking where their teenagers are driving and when they will return home. But the research suggests that it may be better for parents to impose strict limits on particular risk conditions, even if it means going beyond what state law requires, because teenagers are then less likely to become risky drivers or get involved in a motor vehicle crash in the first year after earning a license.

Stress dangers of drinking. This may seem obvious, as the legal drinking age is 21. Still, many teenagers find ways to obtain alcohol anyway. Teenagers (like adults) may not realize they don't have to be legally drunk to become risky drivers; at all blood alcohol concentration levels, they are more likely to crash a motor vehicle or die in an accident.

Restrict night driving. Many crashes take place at night. Ask the teenager to return the car home by 9 p.m. or 10 p.m., regardless of what state law says, until age 18.

Limit passengers. Even one teenage passenger increases risk of a crash, but the risk increases with each additional passenger. (Teenage boys in particular may want to show off for friends or egg one another on.) Ask the teenager to drive alone or with no more than one other passenger at a time, until age 18.

Encourage buckling up. Teenagers are less likely than people of other age groups to use seat belts while driving, with disastrous results. In 2004, nearly two-thirds of teenagers who died or were injured in crashes were not wearing a seat belt.

Monitor sleep. A 2006 poll by the National Sleep Foundation reported that 45% of adolescents said they did not get sufficient sleep on school nights, with 28% saying they felt irritable and cranky as a result. Sleep deprivation in teenage drivers contributes to lack of attention, impaired judgment and greater risk taking, more susceptibility to alcohol intoxication, and increased aggression and impulsivity. This may explain why half of motor vehicle accidents in teenagers occur at night.

Write down "rules of the road." Surveys have found that parents and teenagers may not agree about what rules are in place or what the consequences are for not following them. Although electronic monitoring devices are commercially available, they undermine the development of independence and trust — and few parents use them anyway. It may help to clarify rules, expectations, and conditions for earning increased driving privileges by writing them down. This may not only help teenagers abide by the established limits but also encourage better driving practices.

Graham R, et al. "Preventing Teen Motor Crashes," American Journal of Preventive Medicine (Sept. 2008): Vol. 35, No. 3S, pp. S253–57.

Shope JT, et al. "Teen Driving: Motor-Vehicle Crashes and Factors that Contribute," American Journal of Preventive Medicine (Sept. 2008): Vol. 35, No. 3S, pp. S261–71.

For more references, please see www.health.harvard.edu/mentalextra.