WASHINGTON -- A teenage driver's risk of dying in an accident increases dramatically when there are other teens in the car, and plummets when there's an adult looking on, according to a study by AAA's safety foundation.
Researchers have long known that the presence of other teens is distracting to novice drivers, but most previous studies on the issue are more than a decade old and don't reflect changes in state driving laws that began in the mid-1990s.
Since then, every state has adopted a "graduated licensing" law that places some restrictions on teen drivers.
The laws vary, but typically they restrict teens from driving with any passengers under age 21, or just one young passenger, and bar nighttime driving.
The study by the Automobile Association of America's Foundation for Traffic Safety, being released Tuesday, found what a lot of parents already know: Teens driving with their friends in the car continues to be far riskier than driving alone or with an adult.
The study was based on an examination of government data on teen crashes from 2007 to 2010. Compared to driving with no passengers, a 16- or 17-year-old driver's risk of death per mile driven increases 44 percent when carrying one passenger younger than 21 (and no older passengers), the study found.
The risk is double when carrying two passengers younger than 21, and quadruples when carrying three or more passengers that age. Conversely, the risk of a teen driver dying in an accident when a passenger aged 35 or older is in the vehicle decreases 62 percent, the study said.
Like cell phones, the presence of other teens can be extremely distracting to young drivers, said Jackie Gillan, president of Advocates for Highway and Auto Safety.
Between 2000 and 2010, the number of 16- and 17-year-old drivers involved in fatal crashes each year fell by more than half.
Graduated licensing laws -- as well as greater seat belt use, better safety equipment in cars, and anti-drunk-driving campaigns -- have been credited for the decrease. But 40 percent of the 2,191 younger teen drivers killed during those years had at least one passenger under 21 -- and no older passengers -- in the vehicle, the study said.
And preliminary data for the first six months of 2011 show a small uptick in teen driving deaths, another recent study found.
Just because states have graduated licensing laws "doesn't means everyone is obeying them," said Jonathan Adkins, a spokesman for the Governors Highway Safety Association, which represents state highway safety offices.
"Graduated licensing laws are really good, but we rely on the parents to be the ones enforcing them," he said.
Police can cite teen drivers for violating license restrictions if they pull them over for other reasons, but it's difficult for officers to stop drivers with teen passengers just because they look young, he said.
AAA released the study in conjunction with a rally in Washington to kick off Global Youth Traffic Safety Month.
Summer is the deadliest time of year for teen drivers and their passengers. An average of 422 teens die monthly in traffic crashes during summer compared to an average of 363 teen deaths during the non-summer months.
By JOAN LOWY, Associated Press
Follow Joan Lowy at www.twitter.com/AP-Joan-Lowy.
The Associated Press