EFFECTS OF ALCOHOL ON DRIVING SKILLS

Tests of sensory, perceptual and motor skills were made. Other tests were carried out in a driving simulator for the study of steering performance, a driving simulator for the study of car-following, and in an automobile on the road. Alcohol doses of up to 0.10% BAC were used in these tests. The results showed that there were reductions in the left and right lateral horizontal visual fields of red stimuli; mesopic visual acuity; information processing both in a digit-memory task, and when stimulus response compatibility was decreased in a reaction time test; and a reduction in pursuit tracking ability. The lateral control driving simulator studies showed that drivers changed the cue structure which they used by emphasizing lateral position cues, with a reduction in emphasis on heading angle and yaw rate cues. The drivers under alcohol reduced their responsiveness in manipulation of the steering wheel. The effect was an increase in lateral position and heading angle errors. The effects of the alcohol doses used on the car-following task were less clear. However, spectral analyses indicated that headway errors were greater under alcohol when the frequencies of changes in lead vehicle velocity were above about 0.06 Hz. Below this frequency there were no detrimental effects of alcohol. No effects on lateral path error were found in the car driving study. However, speed maintenance and variability in headway were greater in car-following, which confirms the preliminary findings obtained in the car-following driving simulator tests. There were no significant effects in judgments of the speed of overtaking vehicles seen in rearview mirrors or in passing gap judgments with respect to oncoming vehicles, due to alcohol. These findings are discussed with those of an eye-marker evaluation previously reported. It was concluded that the effect of alcohol was to change the cue structure utilized by the driver for lateral control as well as his responsiveness with the steering wheel to reduce his effectiveness in a manner which mimicked the behavior of a novice driver. This reduction in performance could be expected to lead to an increase in single-vehicle, loss-of-control crashes in which alcohol is often found to be a contributing factor. The car-following tests suggest that drivers at moderate doses of alcohol are likely to introduce perturbations in speed into the traffic stream, thereby increasing the likelihood of rear-end collisions. The study also indicated that the changes in driving performance at 0.071% BAC during alcohol uptake were less severe than at the same BAC during alcohol elimination, showing residual effects of alcohol and fatigue.

  • Supplemental Notes:
    • This report was sponsored by the National Institute on Alcohol Abuse and Alcoholism, Rockville, Maryland.
  • Corporate Authors:

    Highway Safety Research Institute

    Huron Parkway and Baxter Road
    Ann Arbor, MI  United States  48109
  • Authors:
    • Mortiner, R G
    • Sturgis, S P
  • Publication Date: 1975-1-3

Media Info

  • Features: Photos; References; Tables;
  • Pagination: 123 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00096928
  • Record Type: Publication
  • Source Agency: Highway Safety Research Institute
  • Report/Paper Numbers: Final Rpt.
  • Contract Numbers: MH 20660/AA 00295
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM