title: High risk of near-crash driving events following night-shift work.
abstract: Night-shift workers are at high risk of drowsiness-related motor vehicle crashes as a result of circadian disruption and sleep restriction. However, the impact of actual night-shift work on measures of drowsiness and driving performance while operating a real motor vehicle remains unknown. Sixteen night-shift workers completed two 2-h daytime driving sessions on a closed driving track at the Liberty Mutual Research Institute for Safety: (i) a postsleep baseline driving session after an average of 7.6 ± 2.4 h sleep the previous night with no night-shift work, and (ii) a postnight-shift driving session following night-shift work. Physiological measures of drowsiness were collected, including infrared reflectance oculography, electroencephalography, and electrooculography. Driving performance measures included lane excursions, near-crash events, and drives terminated because of failure to maintain control of the vehicle. Eleven near-crashes occurred in 6 of 16 postnight-shift drives (37.5%), and 7 of 16 postnight-shift drives (43.8%) were terminated early for safety reasons, compared with zero near-crashes or early drive terminations during 16 postsleep drives (Fishers exact: P = 0.0088 and P = 0.0034, respectively). Participants had a significantly higher rate of lane excursions, average Johns Drowsiness Scale, blink duration, and number of slow eye movements during postnight-shift drives compared with postsleep drives (3.09/min vs. 1.49/min; 1.71 vs. 0.97; 125 ms vs. 100 ms; 35.8 vs. 19.1; respectively, P < 0.05 for all). Night-shift work increases driver drowsiness, degrading driving performance and increasing the risk of near-crash drive events. With more than 9.5 million Americans working overnight or rotating shifts and one-third of United States commutes exceeding 30 min, these results have implications for traffic and occupational safety.
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115;
authors.forename: Michael L
authors.initials: ML
authors.lastname: Lee
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115; Department of Respiratory & Sleep Medicine, Institute for Breathing & Sleep, Austin Health, Heidelberg, VIC 3084, Australia;
authors.forename: Mark E
authors.initials: ME
authors.lastname: Howard
authors.affiliation: Center for Behavioral Sciences, Liberty Mutual Research Institute for Safety, Hopkinton, MA 01748;
authors.forename: William J
authors.initials: WJ
authors.lastname: Horrey
authors.affiliation: Center for Behavioral Sciences, Liberty Mutual Research Institute for Safety, Hopkinton, MA 01748;
authors.forename: Yulan
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115; Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Clare
authors.initials: C
authors.lastname: Anderson
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115;
authors.forename: Michael S
authors.initials: MS
authors.lastname: Shreeve
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115;
authors.forename: Conor S
authors.initials: CS
authors.lastname: O'Brien
authors.affiliation: Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA 02115; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115; charles_czeisler@hms.harvard.edu.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Czeisler
mesh_terms: D000063:Accidents, Traffic; D000328:Adult; D001334:Automobile Driving / Q000523:psychology*; D001767:Blinking / Q000502:physiology; D004569:Electroencephalography; D004585:Electrooculography; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020178:Sleep Disorders, Circadian Rhythm / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D014481:United States
keywords: EEG; drowsy driving; fatigue; infrared oculography; sleep