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Earlier school start time linked with more teen car crashes, study finds

June 9, 2010 |  5:44 pm

Extra sleep could make students more alert for class, and also for driving. Car crash rates were lower in an area where high school classes started later, according to a new study.

Kswu48nc The study, presented today at the annual meeting of the Associated Professional Sleep Societies in San Antonio, compared crash rates in two Virginia towns: Virginia Beach, where high school classes started at 7:20 a.m., and Chesapeake, where classes started at 8:40 a.m. Teen crash rates in 2008 were about 41% higher in Virginia Beach than in Chesapeake.

Car crash statistics were compiled from the Virginia Department of Motor Vehicles. For every 1,000 teen drivers in Virginia Beach, there were 65.4 car crashes, versus 46.2 crashes for every 1,000 teens in Chesapeake. The neighboring cities share similar demographics.

When researchers broke down the accidents by the time of day they occurred, they found that afternoon crash rates were higher than morning crash rates in both cities. The school day wrapped up in Virginia Beach around 2 p.m., and the afternoon crash rate there was highest from 2 p.m. to 6 p.m. School got out in Chesapeake about 3:40 p.m., and afternoon crash rates there were highest from 4 p.m. to 5 p.m. Overall afternoon crash rates for teens were higher in Virginia Beach than in Chesapeake.

"We believe that high schools should take a close look at having later start times to align with circadian rhythms in teens and to allow for longer sleep times," said Dr. Robert Vorona, the study's lead author. Vorona, associate professor of internal medicine at Eastern Virginia Medical School in Norfolk, Va., warned that the study shows a link between school times and crash rates but does not imply cause and effect. He added, "Too many teens in this country obtain insufficient sleep. A burgeoning literature suggests that this may lead to problematic consequences, including mood disorders, academic difficulties and behavioral issues."

— Jeannine Stein

Photo credit: Mark Boster / Los Angeles Times