Night-shift workers driving home after a night’s work may be at higher risk of crashing due to drowsy driving, according to a small study that evaluated the daytime driving performance of night-shift workers.
The study, led by Brigham and Women’s Hospital (BWH) of Boston, MA, is published in the Proceedings of the National Academy of Sciences.
Researchers compared the daytime driving performance of 16 night-shift workers after a night of work with their performance after a night of sleep.
Results showed that 37.5% of the drivers had a near-crash event when they drove after a night of work, compared with none of the same drivers having a near-crash when they drove after a normal night of sleep.
Most drivers admit they have driven a motor vehicle while drowsy. Within the past year, 28% of American drivers have reported falling asleep at the wheel, say the researchers.
Corresponding author Charles A. Czeisler, a professor of sleep medicine at Harvard Medical School and chief of BWH’s Division of Sleep and Circadian Disorders, says drowsy driving is a major and preventable public health hazard.
He notes that the findings help to explain why night-shift workers have so many more motor vehicle crashes than day workers, particularly during the commute home, medicalnewstoday.com reported.
Previous studies have assessed the effect of night-shift work on driving using driving simulators.
But Czeisler and colleagues believe their results - obtained with subjects driving real vehicles on a test circuit and not in a driving simulator - are the first to show a link between drowsy driving and higher risk of motor vehicle crashes.
For their study, the team, including researchers from the Liberty Mutual Research Institute for Safety in Hopkinton, MA, assessed 16 night-shift workers as they completed two driving sessions, lasting 2 hours each, at the institute’s closed driving track.
The two sessions took place at around the same time of day for each participant, and all participants were accompanied by a driving safety observer who had secondary controls.
Researchers collected measures of drowsiness and driving performance during the driving sessions. The drowsiness measures included electroencephalograms (EEGs) to assess episodes of micro-sleeps and partial eyelid closures with slow eye movements - which indicate transition from wakefulness to sleep.
