Driver fatigue appears to be a dominant causative factor in 10% of serious accidents. If we consider deterioration in performance short of falling asleep, then 20% of serious accidents are fatigue related. However, very little is known about driver fatigue, due mainly to difficulty in measuring changes in driving performance. Driver fatigue has been subjected to theoretical analysis based on both fatigue and alertness concepts. Degree of alertness and performance appear to be directly related, while fatigue has only indirect influence. The performance of a tired driver is not necessarily lower. A diagram summarising data relating to deterioration in performance is presented, based on the assumption that both alertness and tiredness affect physiological processes. It is also not known which variables influence tiredness, and which alertness. Variables are lack of sleep, physical work, diurnal rhythm, medicines, food, age, personality, traffic environment, rest periods, environment in car, speed. Data are also presented concerning the relationship between driving time in a lorry and performance. Reaction times were measured over a total driving period of eleven hours, with a half hour rest after six hours. This is the time permitted by regulations. Results show that deterioration in performance in many drivers is such that traffic safety is threatened. /TRRL/

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  • Corporate Authors:


    Stockholm,   Sweden 
  • Authors:
    • Lisper, H O
  • Publication Date: 1977


  • Swedish

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00193979
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • Report/Paper Numbers: SOU 1977:2
  • Files: ITRD, TRIS
  • Created Date: Jun 13 1979 12:00AM