Three teens were killed after a police pursuit through Chevy Chase ended in a fiery crash in April. (WRC News 4/WRC News 4)

Last month, it was four teenagers in a stolen Toyota who crashed into a Montgomery County tree. Three of them — two were 16, the other 14 — died.

In January, it was three teens on their way home from a birthday party who headed in the wrong direction on a divided highway in Anne Arundel County in the middle of the night, colliding head-on with another car. Everyone died.

For generations, teenagers have been the most dangerous drivers on the road, crashing almost four times as often as older drivers. A study released Tuesday quantifies, for the first time in a decade, how their risk of a fatal crash multiplies when they have other teenagers in the car.

It increases by almost half when a 16- or 17-year-old driver has one teenage passenger; it doubles with two teen passengers; and it quadruples with three or more.

Last year, it was five teenagers in a car that hit a deer and then a tree in Prince William County. Two 15-year-olds were killed. In 2008, a Volvo carrying five teenagers to a Burger King in Montgomery County veered off a winding road and burst into flames after hitting a tree. A 15-year-old passenger died.

“He’s a newer driver,” said the mother of the teenager who was behind the wheel, who survived. “He just miscalculated.”

Using federal fatality statistics, AAA’s Foundation for Traffic Safety provided the data that will support parents who have forbidden their teenage children to drive with other teenagers.

“We know that carrying young passengers is a huge risk, but it’s also a preventable one,” said AAA Foundation President Peter Kissinger. “These findings should send a clear message to families that parents can make their teens safer immediately by refusing to allow them to get in the car with other young people, whether they’re behind the wheel or in the passenger seat.”

The AAA study is the latest of three recent reports to raise concerns about teenage drivers. In reviewing preliminary data from the first six months of last year, the Governors Highway Safety Association found a slight increase in the number of fatal crashes involving 16- and 17-year-old drivers. If the trend continued, it said, 2011 would reverse a recent trend of falling teenage fatalities.

In another study, the National Highway Traffic Safety Administration last month said its research found that drivers under the age of 24 were much more likely than more mature drivers to send and receive text messages while driving.

Overall, highway fatalities fell for the sixth consecutive year in 2011, according to preliminary data NHTSA released Monday. The federal agency said that 32,310 people died in crashes last year, down 375 deaths from 2010. NHTSA will break down the statistics by age group when final data are released later this year.

If the decline in teen fatalities flattens or reverses when that information is released, it might be that the effect of state laws implemented in the past 15 years played out. Graduated licensing laws and requirements for driver education or parental supervision have been mandated in many jurisdictions, including Virginia, Maryland and the District.

“Placing appropriate limits is a key part of graduated driver licensing in the District of Columbia, Virginia and Maryland,” said John B. Townsend II of AAA Mid-Atlantic. “It’s critical that parents enforce the law and family rules.”

In addition, most states have limited the number of non-family passengers who can be carried by teen drivers.

Staff researcher Madonna A. Lebling contributed to this report.