When shopping for a safe car for their teens, parents might want to aim for the newest model they can afford, a new study suggests.

Researchers found that that almost half of the teenage drivers killed on the roads in the past few years were driving vehicles that were 11 or more years old and lacking key safety features found in newer models, according to the study, published online in the journal Injury Prevention.

“We know that many parents cannot afford a new vehicle,” said the study’s lead author, Anne McCartt, senior vice president for research at the Insurance Institute for Highway Safety. “Our message to parents is to get the most safety they can afford.”

McCartt and her coauthor analyzed data from 2008 to 2012 from the U.S. Fatality Analysis Reporting System, which included information on 2,420 drivers ages 15 to 17 and 18,975 drivers ages 35 to 50.

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Among the teens who died, 64 percent were in a car, 29 percent in a mini or small car, and 35 percent in a mid-size or larger car. Most of the teen drivers who were fatally injured — 82 percent — were in vehicles that were at least 6 years old, while 31 percent were in vehicles 11 to 15 years old. For comparison, fatally injured teens were almost twice as likely as their middle-aged counterparts to be driving a car that was 11 to 15 years old.

The most startling statistic: Nearly half of the teens who died — 48 percent — were in a vehicle that was at least 11 years old.

What the researchers don’t know is what percentage of teens drive older vehicles. So they can’t say that the data prove that older vehicles are increasing the risk of death in teenagers.

Still, there’s good reason to suspect that teens would be safer in newer cars, says Tony Fabio, an assistant professor of epidemiology in the graduate school of public health and director of the Center for Injury Research Community Action at the University of Pittsburgh Medical Center. Fabio is unaffiliated with the new study.

“We know that teens are less likely than adults to be wearing seat belts and that may be partially because they are driving older cars in which the belts may not work as well,” Fabio said. “And you have to think about that in the context of an older car that might not have an air bag.”

And while the study doesn’t prove that older cars are less safe, it does suggest they are, Fabio says, adding “almost any major public health victory started out with a study that just suggested something wasn’t safe.”

Ultimately, McCartt said, though newer model cars tend to have more safety features, protecting your teens is not as straight forward as just steering clear of older vehicles. “We did find older vehicles that met our safety criteria,” she said.

Still, it’s a rare older vehicle that has electronic stability control — an important safety feature that helps drivers keep control in extreme maneuvers, McCartt said. “That’s something that is standard on new cars since it was a requirement starting in 2012,” she added.

To help parents figure out which vehicle might be best for their teens, the IIHS came up with a list of safe cars which it posted on its website:

http://www.iihs.org/iihs/ratings/vehicles-for-teens