title: Role of drowsy driving in traffic accidents: a questionnaire survey of Thai commercial bus/truck drivers.
abstract: OBJECTIVE
  The authors assessed the relationship between traffic accidents and drowsiness.
  
  
  METHODS
  A self-answered questionnaire survey of 4331 commercial bus/truck drivers was done.
  
  
  RESULTS
  Sixty-nine percent of the drivers reported accidents and one third of these accidents was attributable to drowsiness. Drowsy driving and microsleeps were experienced by 75% and 28% of drivers respectively. Forty-five percent of drivers had excessive daytime sleepiness based on the Epworth Sleepiness Scale (ESS score > or =11). This excessive daytime sleepiness was strongly associated with feeling drowsy, microsleeps, and accidents. The major causes of drowsiness were sleep deprivation (90%), medications that caused sleepiness (78%), drinking alcohol the previous night (23%), and chronic loud snoring with or without obesity (17%). 61% of drivers worked longer than 12 hours with no days off The feeling of drowsiness at the wheel was also closely related to long hours of driving (>4 hours). Countermeasures that drivers used to keep them awake were talking to someone, drinking coffee or caffeinated-energy drinks, chewing snacks or gum and pulling over to have a nap.
  
  
  CONCLUSIONS
  There is a strong relationship between accidents and drowsiness in commercial bus/truck drivers. The main cause of drowsiness was sleep deprivation. The authors hope that this information will help the public authority develop a policy to reduce the traffic accidents attributable to drowsy driving in commercial bus/truck drivers.
authors.affiliation: Department of Medicine, Vichaiyut Hospital, 71/3 Setsiri Rd, Phyathai, Bangkok 10400, Thailand. manoonlee@yahoo.com
authors.forename: Manoon
authors.initials: M
authors.lastname: Leechawengwongs
authors.forename: Evelyn
authors.initials: E
authors.lastname: Leechawengwongs
authors.forename: Chakrit
authors.initials: C
authors.lastname: Sukying
authors.forename: Umaporn
authors.initials: U
authors.lastname: Udomsubpayakul
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D000328:Adult; D001334:Automobile Driving / Q000523:psychology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016272:Occupational Health; D012892:Sleep Deprivation; D012894:Sleep Stages / Q000502:physiology*; D011795:Surveys and Questionnaires; D013785:Thailand / Q000453:epidemiology