Switching the Clocks Twice a Year Isn’t Just Annoying. It’s Deadly.
An hour of the day will be unceremoniously snatched away on Sunday as we “spring forward” to daylight saving time.
Polling shows that more than half of Americans want to “ditch the switch” and prefer daylight saving over standard time by a margin of 10 to 20 points. But making that switch permanent would require an act of Congress, and while the Senate managed to pass a bill called the Sunshine Protection Act two years ago, the legislation never made it through the House. Worryingly, state legislators from Maine to the West Coast are now so fed up with waiting that they have introduced their own bills to remain on standard time permanently; states can do that without Congress.
But such a switch would be a mistake. It’s not just that our afternoons and evenings would be shrouded in more darkness, which often comes with higher crime, more vehicle collisions and fewer opportunities to enjoy the outdoors after work or school. There’s another problem with standard time, and it’s gone all but unnoticed until now. Last year, my research team showed that standard time leads to far more vehicles colliding with deer.
Vehicle strikes already kill millions of wild animals each year, and collisions with deer are the best documented because they are so common and damaging. When we looked at over one million collisions between deer and vehicles in 23 states across the United States between 1994 and 2021, we found these collisions are 14 times as likely in the two hours after sunset, compared to the two hours before. Deer behavior does not quite explain this, since they are equally active at dawn and dusk. But traffic volumes are higher in the evening, and it’s hard for us to see things in the dark. The hour-earlier sunset that comes with standard time is thus an expensive, traumatic way to control the deer population.
In all, we found that staying on daylight saving time year-round would prevent an estimated 36,550 collisions between deer and vehicles, whereas staying on standard time would add 73,660 of these collisions every year — a difference of more than 100,000. The human toll of staying on standard time would also be significant: Compared to year-round daylight saving time, year-round standard time would cause 100 more deaths, 6,000 more injuries and at least $3.5 billion in costs every year through increased deer-vehicle collisions alone.
Of course, more crashes with deer is far from the only cost of standard time. The number of fatal traffic accidents at night — caused by deer or anything else — is three times higher than it is during the day, and the dark increases the risk of pedestrian accidents by up to seven times. Permanent daylight saving time would prevent 366 fatal pedestrian and vehicle accidents a year with the help of brighter evenings during the 4.5 months of the year we currently spend on standard time. Conversely, staying on standard time for an extra 7.5 months each year would add about 610 fatalities — a difference of nearly 1,000 human lives.
