BOSTON (CBS) – Motor vehicle crashes are a leading cause of death in adolescents, but according to a new study, if teens are allowed to sleep in later on school days, they may get into fewer car accidents.

Researchers at Boston Children’s Hospital analyzed car accidents involving teenagers for two years before and after school start times were delayed in Fairfax County, Virginia. They found that the crash rate among 16-to-18 year olds fell significantly with the hour-later start time.

They said teens that get more sleep are less likely to make bad decisions, like using smartphones while driving or not wearing seat belts.

The American Academy of Sleep Medicine supports start times of 8:30 a.m. or later for middle and high school students and recommends that teens get 8 to 10 hours of sleep a night.

Dr. Mallika Marshall