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What Science Can Tell Us About Teen Drivers

Inexperience behind the wheel is one thing, but short attention spans, distracting emotions and undeveloped frontal lobes may also impact young drivers

When government researchers asked a sample of teens to use a smartphone while driving on a test course, the group performed remarkably well—on the smartphone tasks. They dialed numbers correctly, sent texts, looked up information online and did everything else the researchers asked. Adults in the same study didn’t fare so well with the smartphone, but they did obey every stop sign on the course. The phone-savvy teens, on the other hand, blew through 30 percent of the stop signs.

“Inexperienced drivers are much more comfortable with taking their eyes off the road,” notes Bruce Simmons-Morton, the study’s coauthor and a senior investigator specializing in teen driving at the National Institute of Child Health and Human Development (NICHD). “When teens are faced with a secondary task, like using the phone or reaching for something in the car, they’re not very good at splitting their attention. Secondary tasks are dangerous for all drivers, but adults are less likely to look away from the road while attempting them.”

 

That’s just one of Simmons-Morton’s findings that might explain why vehicle crashes are the leading cause of death and disability among adolescents aged 16 to 18, according to the Centers for Disease Control. (See The New England Journal of Medicine for the full text of the study and a teen-friendly video on the dangers of distracted driving.)

10,000+ Hours of Driving Experience Counts

 

Simmons-Morton says novice drivers of any age are at higher risk for crashes. “Driving is a complex motor activity, just like tennis or golf,” he explains. “It’s easy enough to learn on a functional level, but difficult to master. You can expect to be at your peak after about 10,000 hours of practice. That’s true whether you’re talking about driving or basketball.”

He describes the first six months of licensure—or roughly 1,000 hours of driving—as “hugely dangerous.” According to his research, crash rates start to decline after that point, but don’t drop to adult levels until drivers have on average five to six years of experience under their belt. “It usually takes that long to get over the 10,0000-hour hump,” Simmons-Morton explains.

This Is the Teen Brain on the Road 
 

NICHD researchers have studied the difference between novice teen drivers and novice drivers in their early 20s. Both groups have very high crash rates that decline over time, but the decline is slower among teens. “All novices are at risk, but especially adolescents. They are inexperienced at things besides driving, like managing passengers and dealing with emotions. They simply have less experience at life and fewer resources to draw upon.”

He also points to a key neurological difference between teens and adults. “We know from brain imaging studies that the frontal lobe isn’t fully developed until your early twenties. That means teens might be less likely to make rational decisions in emotional situations. That’s an issue for all of us, but more so for adolescents.”

Teens who drive with multiple teen passengers face higher risks. With three teens in the car, the crash rate is three to four times higher than that of a teen driving alone.

"...The frontal lobe isn’t fully developed until your early twenties. That means teens might be less likely to make rational decisions in emotional situations."
— Bruce Simmons-Morton, senior investigator, NICHD

Why Some Teens Learn Safe Driving Faster Than Others


Despite having high crash rates as a group, some teens drive just as safely as adults, according to Simmons-Morton’s research. “The majority of adolescents manage themselves quite well from the start,” he says. “Then there’s another group that takes a while to get it. They make a lot of mistakes in the first six months, but are good after that. The third group starts out bad and stays there for at least 18 months, which is as long as we’ve been able to study them.

”He notes that most teens tend to drive alone or with one passenger, but those in the high-risk group are more likely to drive with multiple teen passengers. “Once you have three teens in the car, the crash rate is three to four times higher than with a teen driving alone.” His research also shows that drivers in this group engage in secondary tasks more frequently, which compounds the risk.  

What Parents Can Do Right Now


“Parents can become better coaches,” says Tim O’Neil, a professional driver and instructor for 37 years who runs the Team O’Neil driving school in Dalton, NH. “Coaching can start as soon as a child is legally old enough to sit in the front seat. Parents should explain their actions, like why they’re slowing down or checking the rearview mirror. It’s amazing how much a kid can pick up before he or she steps a foot in driver’s ed class.”

 

Likewise, parents with unsafe or risky driving habits can rub off, says O’Neil. “Those bad habits can  show up in your teen’s driving,” says O’Neil.

 

“We know that teens with involved parents drive more safely and have fewer crashes,” says Simmons-Morton. “Restrictions like curfews and passenger limits are effective, but it’s up to the parent to enforce them.” To formally establish the rules and expectations, he references parent-teen driving agreements like this downloadable template from the Centers for Disease Control and Prevention.

 

Another option is installing a driving behavior feedback device that records both the driver and the roadway during elevated g-force events like swerving and sudden braking. Simmons-Morton’s research has found these devices are most effective when teens and parents view and discuss the feedback together.