Researchers say their recent study into night shifts and drowsy driving has implications beyond those who work primarily when it’s dark.
Take employees who regularly works the overnight (most commonly 11 p.m. to 7 a.m.) shift. Monitor their driving after a night shift.
Take the same employees, have them get a good night’s sleep and monitor their driving after that.
Now compare the two.
That’s exactly what scientists from the Liberty Mutual Research Institute for Safety (LMRIS) and Brigham and Women’s Hospital did.
Sure, you’re saying to yourself. Those two instances of driving are going to be different.
It’s not just that they’re different. It’s how different the researchers found they were.
Almost 40% of drivers who operated a vehicle on a closed test track after working the night shift were involved in near-crashes. The same drivers with normal sleep had zero near-crashes.
“While we expected differences between the two driving conditions, the sheer magnitude of that difference – 40% versus 0% – is striking,” said William Horrey, project co-investigator and principal research scientist at LMRIS.
After completing a night shift, the workers had:
- more episodes of prolonged blinking
- more frequent slow eye movements, and
- twice the number of lane departures.
The workers also had increased risk of microsleep after a half hour of post-night-shift driving.
How dangerous is microsleep? At 65 miles per hour, a three-second microsleep results in 286 feet of travel – almost the length of an NFL football field.
“It’s vital for night shift workers to schedule uninterrupted sleep on weekdays to allow for complete recuperative rest,” said David Lombardi, LMRIS research scientist and an expert on shift work fatigue.
But today, more workers face potential fatigue similar to what night-shift employees experience.
“In today’s hyperproductive society, many people are convinced that they can operate effectively on just four or five hours of sleep,” said Ted Kwartler, Liberty Mutual’s manager of its Next Generation Vehicle Program.
For now, night shift workers can take steps to make sure they are less likely to drive drowsy and experience microsleep:
- Adhere to a structured daytime schedule that prioritizes sleep
- Get your family and friends to understand and support your need to get rest during daytime hours, and
- Have a back-up plan for transportation home after your night shift in case your feel drowsy. This can include calling someone else to drive you, catching a ride with a co-worker or using mass transit.
In the future, technology may help overcome this problem. Kwartler says more analysis of the data from this study will help direct future vehicle technology and innovation.
Future generation vehicles may incorporate driver-sensing technology.
This study was published in the Proceedings of the National Academy of Sciences.