title: Adolescent sleep, school start times, and teen motor vehicle crashes.
abstract: OBJECTIVE
  To assess the effects of delayed high-school start times on sleep and motor vehicle crashes.
  
  
  METHODS
  The sleep habits and motor vehicle crash rates of adolescents from a single, large, county-wide, school district were assessed by questionnaire before and after a 1-hour delay in school start times.
  
  
  RESULTS
  Average hours of nightly sleep increased and catch-up sleep on weekends decreased. Average crash rates for teen drivers in the study county in the 2 years after the change in school start time dropped 16.5%, compared with the 2 years prior to the change, whereas teen crash rates for the rest of the state increased 7.8% over the same time period.
  
  
  CONCLUSIONS
  Later school start times may both increase the sleep of adolescents and decrease their risk of motor vehicle crashes.
authors.affiliation: Department of Educational and Counseling Psychology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Danner
authors.forename: Barbara
authors.initials: B
authors.lastname: Phillips
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D001334:Automobile Driving / Q000706:statistics & numerical data*; D003625:Data Collection; D005260:Female; D006801:Humans; D007629:Kentucky; D008297:Male; D012574:Schools / Q000458:organization & administration*; D012890:Sleep / Q000502:physiology*; D013997:Time Factors