Driving with a couple of friends in the car can triple a teen’s risk for a fatal crash. That’s the reason behind tough teen driving laws in Pennsylvania and New Jersey. Both states put some limits on passengers in the cars of new drivers — and Pennsylvania beefed up its rules in late December. But eye-opening new studies from the Children’s Hospital of Philadelphia suggest that it takes more to protect young drivers — and the motorists around them — from one of the biggest causes of teen traffic accidents and deaths: the other kids in the car.

Giving friends a lift is a rite of passage for high school juniors and seniors, but it’s also risky business. Fatal crashes are already the #1 cause of death among teens ages 16 to 19. Young drivers are more likely to speed, run red lights, swerve, tailgate and drive under the influence of alcohol and/or drugs when their buddies are on board. The result: For a 17-year-old driver, fatal accident risk goes up 48 percent with one young passenger, doubles with two and triples with three or more.

What’s happening when teens drive with teens? Researchers from CHOP’s Center for Injury Research and Prevention recently found:  

Teens who say “hop in” are more likely to be thrill-seekers. In a survey of 198 teenage drivers, the researchers found that a minority were likely to drive with plenty of friends. These drivers described themselves as thrill-seekers. What parents should know: They also said their parents did little to set driving rules or keep tabs on them. And they didn’t have a strong sense of the dangers.   

Drivers are – no surprise here – more distracted with friends in the car. The researchers also looked at 677 teen drivers who had been 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,” noted study author Allison Curry, PhD, director of epidemiology at the Center for Injury Research and Prevention.  “Among the 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 directly by the actions of their passengers.”

Here’s the kicker: Graduated driving laws that set limits on young drivers help but don’t go far enough, the researchers say. “Parents should not just defer to GDL laws or rely on police enforcement; parents need to actively clarify rules and expectations,” they note. Parent-teen driving contracts might help, if teens understand that passengers can be a safety hazard.

New Pennsylvania rules, which went into effect at the end of December, allow a young driver with a learner’s permit just one under-18 passenger (siblings excluded) for the first six months unless a parent or guardian is in the car. After that, more are OK. In New Jersey, teens with a practice permit can have just one other peer in the car, unless a parent or guardian’s riding along, too. Once a New Jersey driver has his or her basic license (at age 18), there are no limits on passengers.

What do you think? Do you set stricter rules for teen drivers in your household? Should laws go even further to limit passengers?