Related Experiment Video
Updated: Jun 26, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
Adolescent sleep, school start times, and teen motor vehicle crashes
Fred Danner1, Barbara Phillips
1Department of Educational and Counseling Psychology, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY 40536-0298, USA.
Study Objectives:
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.
Related Concept Videos
Insufficient Sleep and Sleep Deprivation
Sleep deprivation is a more severe form of sleep loss...
Substance Use Disorders Affecting Sleep
Understanding the concepts of physical dependence,...
Sleepwalking and Sleep Talking
Factors that increase the likelihood of sleepwalking include sleep deprivation and alcohol consumption. Contrary to common beliefs, it is safe...
Sleep Apnea
The condition is more prevalent among...
Narcolepsy
Nightmares and Night Terrors
Nightmares often...

