You've lectured your teen ad nauseam about not texting and driving. But even if he hews to this rule, other teens don't. If your kid ends up a passenger in a car with one of them, what should he do?

It's an important question, since car crashes remain the leading cause of death for 16- to 19-year-olds, primarily due to risk-taking and distraction. A 2015 study by AAA Foundation for Traffic Safety found distraction factored into six out of 10 crashes involving teens.

In a 2014 study by Safe Kids Worldwide, 49 percent of teens reported feeling unsafe with a teen driver and 39 percent reported riding with a teen driver who was texting. Many passengers did not speak up.

Here are some strategies your teen can use to stop a dangerous situation without losing "cred," courtesy of Jessica Mirman, PhD, a developmental psychologist at the Center for Injury Research and Prevention and Division of Adolescent Medicine at The Children's Hospital of Philadelphia.

For teens, making good choices in the face of social pressure is easier if they're not thinking through a situation for the first time when they're in it. Talk through these strategies with your teen in advance to boost his or her confidence in using them, says Mirman.

Related: 7 Ways to Prevent Your Teen from Texting and Driving

Try to read the driver before getting in the car. It’s better to avoid getting into a dangerous situation to begin with. For example, if a driver is texting as she’s opening the car door, your teen can wait before getting in. “The passenger can say something like, ‘I don’t mind waiting for you to finish up,’” suggests Mirman. “They can say it gently and be subtle.”

Be a “helpful” passenger. Help your teen cultivate the idea that friends have each other’s backs and won’t let one another make a risky choice. They can frame their safety concerns as support or even a return favor for the ride. For example, if a friend’s phone chimes while she’s driving and she wants to check it, your teen can volunteer to be her designated communicator. “Say something like ‘Hey, you’re busy, why don’t I do this for you? I don’t mind,’” Mirman suggests.

Make up the need for a stop. If the friend won’t listen and the situation feels dangerous, the teen should tell the driver he needs to make a stop — perhaps at a nearby store for a forgotten item. Once the car stops, the driver will have time to finish using his phone, and your teen can take time to compose himself, think about what he wants to say or find another, safe ride, Mirman says. Your family can also set up a code word for teens to use in dicey situations so you can bail them out if they call you for help.

Related: The Scary Truth About Teen Drivers, and How You Can Keep Them Safe

Mom and dad, do your part

This will no doubt surprise some parents: In the Safe Kids Worldwide study, 31 percent of teens reported feeling unsafe with a parent driver.

To help teens be proactive, responsible passengers, start by modeling good habits, such as consistent seat belt use and no cellphone use. When parents stay involved, set rules and demonstrate support, they cut their teen driver’s risk of a crash in half, CHOP’s research shows.

Finally, talk with teens about what qualifies as distracted driving. Many teens see texting at a stoplight as acceptable because they’re not moving, or they believe reading a text isn’t as dangerous as sending one. But 46 states ban texting while driving, and that includes texting at stoplights and reading texts.

Related: Can’t Stop Texting and Driving? This Device Is For You

Joanna Nesbit is a freelance writer specializing in education, parenting, lifestyle and family travel.