Colorado State Patrol examines theory that fatal crashes rise after daylight savings
This coming Sunday, March 8, Colorado will “spring forward” one hour for daylight savings time, and we will all lose an hour of sleep. While the time change can throw off schedules for appointments or events, researchers have suggested that the switch can also increase fatal crashes each year.
“A few years ago The University of Colorado Boulder published a study that linked an increase in deadly crashes to daylight savings,” explained Col. Matthew C. Packard, chief of the Colorado State Patrol. “Troopers see hundreds of crashes each year caused by falling asleep or being drowsy behind the wheel. Drivers shouldn’t underestimate the value of a good night’s sleep.”
In 2025, the Colorado State Patrol investigated 755 crashes involving fatigue, with 202 people injured and 13 people killed. These crashes increased 6.7% over 2024.
Focusing on the impacts of Daylight Saving Time, the Colorado State Patrol decided to take a closer look at crashes investigated by troopers. The Patrol pulled 10 years of crash data for the workweek (M-F) before and after Daylight Saving Time. The data table below shows that the ten-year tally of fatal crashes before DST and after DST increases by 25.9%.
Only two years, 2020 and 2022, had higher fatal crash counts the week before DST than the week after. The year 2020 is easy to understand because COVID-19 drove travel down at exactly that time. In 2019 and 2021, the weeks before and after DST had equal fatal crash counts. The other six years all showed an increase in fatal crashes the week after DST.
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