Motor-vehicle crashes are the leading cause of death among adolescents in the United States, accounting for nearly 5,000 fatalities and over 400,000 injuries annually among teens 16 and older. The crash rate for teen drivers is four times higher than for older drivers.

But studies show that it’s more than just teen drivers who are at risk — 40 percent of teen motor-vehicle deaths involve passengers.

Overall, 59 percent of students always used seat belts when driving, but only 42 percent always buckled up as passengers, the researchers found. Only about one out of three students said they always wore seat belts whether driving or riding as a passenger.