Making daylight saving time permanent could drastically reduce deer collisions, a study finds

Drivers would strike and kill 37,000 fewer deer each year if the United States kept DST all year round, according to estimates in a new study published Wednesday in the journal Current Biology.

The study predicts that maintaining daylight saving time all year round – and reducing the amount of time rush hour traffic takes place during darkness – would prevent 33 deaths and about 2,000 people injured and save about 1. , $ 2 billion in collision costs.

“The numbers are surprisingly large,” said Laura Prugh, associate professor of wildlife sciences at the University of Washington and author of the study. “It is barely apparent that a seemingly simple change – not turning the clock back in the fall, not turning back – would lead to such a marked reduction in collisions across the country.”

Research highlights how subtle changes in human behavior can have a major impact on animals. It also adds more ammunition to the heated debate about seasonal time changes and could bolster the political arguments for the U.S. switch to permanent daylight saving time.

Daylight saving time is when many parts of the world set their clocks forward one hour to move sunlight later in the day.

The US Senate passed a bipartisan bill in March that would make DST standard for all states except Arizona and Hawaii. The Chamber did not put forward the Sunshine Protection Act.

Watches nationwide will fall on Sunday.

About 2.1 million car accidents in the United States each year involve deer, the study says. These incidents cause 440 human deaths each year.

To understand the effect of seasonal time changes, the researchers collected wildlife and vehicle collision data from 23 states and then created a model to estimate impacts nationwide.

Deer are most active on both sides of sunrise and sunset, and data showed that drivers are much more likely to hit deer when it is dark.

“If you drive two hours after sunset, you are 14 times more likely to hit a deer than if you drive before sunset,” said Calum Cunningham, postdoctoral researcher at the University of Washington and author of the study.

The data also showed that traffic accidents involving deer increased in the fall.

For deer, there could be no worse time of year when humans suddenly change their schedules.

“The time change occurs practically exactly in the middle of the mating period, particularly for white-tailed deer,” Cunningham said.

During the rut, as the mating season is called, the male deer “go a little crazy, increase their movements and are fixated on breeding,” he said.

Deer move about 50 percent more on the track and are more vulnerable to being hit by vehicles, the study says.

This means that when people’s schedules change to standard time, the clock aligns heavier traffic with darkness and during the peak of the mating season. The researchers found that collisions with deer increased by about 16% in the week following the exchange.

“It’s like the perfect storm. These deer are going crazy. They really are more at risk already and we have this further change to add more driving after dark in this change, ”Cunningham said.

After the time change, fewer deer are killed in the morning because there is more light. But not enough motorists left before dawn to compensate for the increase in collisions during the evening rush hour.

Northern US states would reduce collisions more from permanent daylight saving time. Locations at the eastern end of their time zone, where it gets dark earlier, would also benefit more.

Some states don’t keep high-quality data on wildlife incidents, so the overall numbers in the study are only estimates. But the trend found by the researchers parallels that found by a separate analysis in upstate New York.

Tom Langen, a biology professor at Clarkson University who studied the effect in the state, praised the new study, saying it answered questions about what impact it would be nationally and did a good job taking into account the gaps in the state. data.

“The underlying message is that it’s a big number,” he said. “It is probably correct that the shift of the time, and in particular the shift from summer time to winter time in the fall, causes some human deaths and many accidents that would not happen.”

Doctors and researchers, particularly those of the American Academy of Sleep Medicine, have opposed the permanent switch to summer time. They argue that solar time is more beneficial to health because our bodies function better with more sunlight in the morning.

But a change to the permanent standard time would significantly worsen collisions between deer and vehicles, the model predicts, causing nearly 74,000 more accidents, 66 human deaths and more than 4,100 injuries.

“Overall, we need a comprehensive cost-benefit analysis of how DST affects our health and the environment,” said Cunningham.

CORRECTION (Nov 2, 1:21 pm ET): An earlier version of this article incorrectly stated how DST works. Clocks are advanced one hour in spring and back one hour in autumn.

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