The experiment investigates the ability of subject drivers to perform a two-lane passing task, with oncoming traffic, as a function of the level of ambient illumination and the headlight intensity of the oncoming vehicle. Eight experienced drivers perform both passing trials and gap-estimation trials, under closed-course conditions, during dawn and dusk hours. Levels of ambient illumination vary from approximately . 02 to 200 foot candles during the experiments. Headlight conditions included no lights, normal low-beam headlights and low-beams with filters which reduced their intensity to about 1/3 of normal. Results indicate that the gaps accepted by drivers in a two-lane passing situation increase with an increase in the intensity of the headlight of the oncoming vehicle. The range of gaps accepted across headlight conditions is smaller, however, at higher levels of ambient illumination than at lower levels. Best results in terms of mean gaps accepted and minimum variability in performance are achieved with the reduced intensity low-beams. Results are discussed in terms of the optimum intensities of daytime running-lights. Suggestions for future research are presented.

  • Supplemental Notes:
    • Proceedings of the 6th Congress of the International Ergonomics Association and Technical Program of the 20th Annual Meeting of the Human Factors Society, July 11-16, 1976, at the University of Maryland, College Park.
  • Corporate Authors:

    International Ergonomics Association

    41 rue Gay-Lussac
    F-75 Paris 5e,   France 

    Human Factors Society

    1134 Montana
    Santa Monica, CA  United States  90403
  • Authors:
    • ATTWOOD, D A
  • Publication Date: 1976-7-11

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00156382
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Oct 29 1977 12:00AM