Daylight saving time is a mess. It ruins your sleep. It triggers an annual wave of terrible retail puns. And despite decades of claims that it saves energy, the data simply doesn’t back that up. So why do we keep doing it?
Maybe we shouldn’t. Not just because it’s annoying, but because it might be killing people.
When the clocks spring forward in March, we lose an hour of sleep. That sounds trivial. One hour. But your body doesn’t adjust in a day. Research suggests it takes several days to realign your circadian rhythm. During that window of grogginess, car crashes spike. The risk is highest immediately after the shift.
The Cost of Springing Forward
A study from the University of Colorado Boulder looked at traffic data between 2002 and 2011. The findings were stark. Over ten years, an estimated 302 deaths could be attributed to the daylight saving transition. That’s more than 30 fatalities per year linked directly to the time change.
The U.S. government’s Fatality Analysis Reporting System (FARS) tells a similar story. The Monday after clocks move forward sees a 17 percent jump in traffic-related deaths. Fatalities remain elevated throughout that entire week.
Why does this happen? It’s not just darkness. While it is true that drivers are now facing earlier, darker commutes, visibility isn’t the main culprit. Experts point to sleep deprivation. Drivers are fighting to stay awake. Some police departments report a 10 percent increase in crashes in the days following the shift. You are essentially asking tired people to operate heavy machinery.
Morning Traffic is More Lethal
The danger isn’t confined to just one week. A 2020 study published in Cell Biology examined motor vehicle fatality data from 1996 to 2017. They found a 6 percent increase in traffic deaths during the first week of daylight saving time. That translates to roughly 28 extra deaths every year.
Here is the tricky part: most of these fatalities occur in the morning.
The risk drops the week after the time change settles in. Interestingly, the reverse shift in the fall—when we “fall back” and gain an hour of sleep—does not show a subsequent increase in traffic deaths. The loss of sleep appears far more dangerous than the gain.
Who Is Most at Risk?
The grogginess you feel after the time change might be just the tip of the iceberg. Sleep needs vary by individual, and the disruption hits everyone differently.
People who normally get only four or five hours of sleep are at significantly higher risk of causing a crash than those who sleep six or seven hours. Those who regularly get eight hours or more are the least likely to be involved in an accident. But when you disrupt the cycle, everyone suffers. The buffer for error shrinks.
The statistics suggest that daylight saving time is more than a minor inconvenience. It’s a public safety hazard. Perhaps it is time to abolish it entirely. Or at least, to stop pretending it serves a useful purpose.
