SUNDAY, Jan. 29, 2012 (HealthDay News) -- Teens who think of themselves as thrill-seekers and who believe their parents don't set rules are among the most likely to drive with other teens in the car, which in many states violates graduated licensing laws, a new study finds.
And a second study of teens involved in serious accidents found that for those carrying other teen passengers, distraction and risky driving behavior often played a role.
It's long been known that having teen passengers increases a teen driver's crash risk, according to Children's Hospital of Philadelphia researchers, but it hasn't been well understood how this these passengers actually increase crash risk.
"These studies help us understand the factors that may predispose teens to drive with multiple friends and how those passengers may contribute to crashes by distracting the driver and promoting risky driving behaviors, such as speeding, tailgating or weaving," study author Allison Curry, director of epidemiology at the Center for Injury Research and Prevention, said in a hospital news release.
"Knowing this, we can develop programs that work in tandem with current graduated driver licensing laws that limit the number of passengers for teens during their first year of driving," she added.
In the first study, Curry and colleagues surveyed 198 teen drivers and found that those mostly likely to transport their friends shared a number of characteristics. They considered themselves thrill-seekers, said their parents didn't set rules or monitor their whereabouts, and had a poor understanding about the overall risk of driving.
"The good news is that that these teens make up the minority," study author and behavioral researcher Jessica Mirman said in the news release. "Teens in this study generally reported strong perceptions of the risks of driving, low frequencies of driving with multiple passengers and strong beliefs that their parents monitored their behavior and set rules."
The second study looked at a nationally representative sample of 677 teen drivers involved in serious crashes.
Both male and female teen drivers with peer passengers were more likely to be distracted just before a crash as compared to teens who crashed while driving alone, according to the study. Among teens who said they were distracted by something inside the vehicle before they crashed, 71 percent of males and 47 percent of females said they were distracted by the actions of their passengers.
The survey also found that male drivers with passengers were nearly six times more likely to perform an illegal driving maneuver and more than twice as likely to drive aggressively just before a crash compared to males driving alone.
Females rarely drove aggressively, regardless of whether they had passengers in the car.
"Most teens take driving seriously and act responsibly behind the wheel. However, some may not realize how passengers can directly affect their driving," Mirman said. "Teen passengers can intentionally and unintentionally encourage unsafe driving. Because it can be difficult for new drivers to navigate the rules of the road and manage passengers, it's best to keep the number of passengers to a minimum for the first year."
The studies, conducted with State Farm, were published Jan. 24 in the Journal of Adolescent Health.
The Nemours Foundation offers parents a list of rules for teen drivers.