Teen drivers who start class earlier in the morning are involved in significantly more motor vehicle accidents than peers with a later high school start time, a new US study has found.
Researchers found that sleep loss during the school week may contribute to teen drowsy driving risk.
Results show that the weekday crash rate for teen drivers during the 2009 to 2010 school year was about 29 per cent higher in Chesterfield County, in Virginia, where high school classes began at 7:20 am, than in adjacent Henrico County, Virginia, where classes started at 8:45 am.
Similar results were found for the 2010 to 2011 school year, when the weekday crash rate for 16-17 year old teens in Chesterfield County was about 27 per cent higher than for those in Henrico County.
In contrast, there was no difference in adult crash rates in the two counties for either year.
A secondary analysis evaluating the causes and types of crashes found that Chesterfield County adolescents had a significantly higher rate of run-off-road crashes, which is a common feature of drowsy driving accidents.
"There are more and more data suggesting that insufficient sleep is common in our teens and that early high school start times are a contributor to teens' reduced sleep," said principal investigator and lead author Dr Robert Vorona, associate professor in the Division of Sleep Medicine at Eastern Virginia Medical School in Norfolk, Virginia.
"Insufficient sleep appears to have deleterious consequences such as decrements in mood and increased risk taking, impaired academics and increased crash rates," said Vorona.
The study involved an analysis of data provided by the Virginia Department of Motor Vehicles.
During both school years there were more than 520 motor vehicle accidents involving teen drivers in Chesterfield County and more than 320 teen crashes in Henrico County.
The study was published in the Journal of Clinical Sleep Medicine.
