Study: Fatal car crashes spike during the week after the clock springs forward

Fatal car crashes in the U.S. spike by 6% during the workweek following the daylight saving time change, resulting in about 28 additional deaths every year, according to a study.

The risk increases the farther west a person lives in a time zone and is worse in the morning, said the study by researchers at the University of Colorado Boulder, which analyzed more than 700,000 fatal crashes reported from 1996 to 2017 .

The increase in crashes could be related to driver sleepiness, as the time shift means that people have to wake up an hour earlier than they’re used to, the study said. It did not find that daylight saving time reduced afternoon rush-hour crashes due to better lighting.

“An hour may not seem like a significant amount of time, but even small changes in our sleeping habits can impact how we feel and, potentially, our reaction time while on the road,” said Trevor Chapman, a spokesman for Farmers Insurance

Group. The insurance company also has found an increase in crashes in the week after compared with the week before the spring time change.

The findings come as several states, including Oregon, California, Florida and Washington, consider doing away with the switch entirely, and a growing body of research shows increases in heart attacks, strokes, workplace injuries and other problems in the days following the “spring forward” change, when clocks are set ahead one hour.

The University of Colorado study, published Jan. 30 in the journal Current Biology, noted that in 2007, the increase in crashes moved from April to March, when the Energy Policy Act extended daylight saving time to begin on the second Sunday of March instead of the first Sunday in April.

Changes in crash patterns also occur after the “fall back” time change, with a decline in morning crashes and a spike in the evening, when darkness comes sooner, the study found. There was no overall change in crashes during the “fall back” week, the study found.

In total, over the 22 years studied, about 627 people died in fatal crashes associated with the spring time shift, the study found.

Last year, state Sen. Andy Manar, a Democrat from Southern Illinois, proposed that the state permanently operate on daylight saving time. The legislation passed the Senate last fall, but fizzled in the House.

If time changes are abolished, it would be better to go to standard time permanently, said Celine Vettel, assistant professor of integrative physiology and senior author of the University of Colorado study. That’s because research has shown that it’s better for sleep, the body clock and overall health to have more morning light and less evening light, Vettel said.

The United States briefly adopted daylight saving time during the World Wars I and II, as a way to save energy, but the issue was otherwise left to local and state governments for several decades. The Uniform Time Act was signed into law in 1966, and the biannual clock adjustment now occurs across the United States.