A new study has found that the annual switch to daylight saving time (DST) is linked to a 6% increase in fatal traffic accidents during the week following the spring clock change. Researchers published their findings in Current Biology, raising concerns about the dangers of sleep deprivation and disrupted circadian rhythms caused by losing an hour of sleep.
The study analyzed over 730,000 fatal car crashes in the United States from 1996 to 2017 and identified a clear pattern: traffic deaths consistently spiked in the week after DST began. The risk was especially high in the morning hours, when drowsy drivers faced darker road conditions. The increase in accidents was more pronounced in western regions of time zones, where sunrise is significantly delayed, forcing commuters to drive in the dark for longer.
“Losing an hour of sleep might not seem like much, but it can have serious consequences,” the study’s authors wrote. They pointed to previous research showing that even minor sleep deprivation impairs reaction time and decision-making, increasing the likelihood of crashes.
The findings add to the growing debate over whether DST should be eliminated. Some lawmakers have pushed for a switch to permanent standard time, arguing that the biannual time change disrupts sleep, health, and public safety. While no federal action has been taken yet, states like California and Florida have considered legislation to end the time change.
With the start of daylight saving time approaching, experts recommend that drivers be extra cautious in the days following the switch, allowing more time for rest and adjusting their morning routines to minimize fatigue.
