ASHLAND, Ore. — When daylight saving time prompts us to lose an hour each spring, the number of car crashes tends to go up, according to a study by a sleep researcher with Oregon Health & Sciences University (OHSU).
Dr. Nancy Knechel works at OHSU's School of Nursing in Ashland. She's been digging into the amount of sleep that people lose every year during the shift, and the effect it can have on people's lives.
A serious injury crash on McAndrews Road in Medford last March (courtesy Spencer Karnafel).
"It’s that time of year again: this Sunday, March 8, we will be changing our clocks forward one hour to mark the beginning of daylight saving time," the researchers said in a statement. "While most people welcome the shift of one hour of daylight from morning to evening, most don’t welcome the hour lost while sleeping that comes with changing our clocks in the spring."
Previous research has shown that people lose an average of 40 minutes to an hour of sleep once daylight saving time begins. Dr. Knechel says that sleep deprivaton can decrease a person's alertness and increase the time it takes to react to sudden stimuli.
"These decrements in physical and mental performance can increase a person’s risk for injury," Dr. Knechel said.
The study looked at six years of the Oregon Department of Transportation's (ODOT) crash data for Jackson County. It found a small but significant increase in the number of motor vehicle crashes between 2013 and 2018 in the work week following following daylight saving time compared to the week prior — an increase to the tune of three percent.
Even removing 2018, the results of which are still considered "preliminary" by ODOT, the spike held true. 2018 itself showed a 3.5 percent increase with that early data.
Dr. Knechel's research also found an increase of more than 5.5 percent in the number of injuries sustained during crashes in the week after daylight saving time.
"These new findings underscore the importance of sleep in everyday functioning. Since even small amounts of acute sleep loss on top of chronic sleep deprivation can have profound consequences, look for opportunities to obtain adequate sleep this week in preparation for the time change on Sunday," Dr. Knechel said.