Yet something even more profound has happened in this ongoing story of later school start times - something that researchers did not anticipate: the life expectancy of students increased. The leading cause of death among teenagers is road traffic accidents, and in this regard, even the slightest dose of insufficient sleep can have marked consequences, as we have discussed. When the Mahotomedi School District of Minnesota pushed their school start time from 7:30 to 8:00 a.m., there was a 60 percent reduction in traffic accidents in drivers sixteen to eighteen years of age.

Why We Sleep by Matthew Walker