Videotaped eye fixations and saccades (30 frames per second) were analyzed for 32 young, healthy drivers, who were unfamiliar with the highway, along rural two-lane highways in Ohio under low-beam illumination conditions at night for the approach to a curve/turn warning sign (curve/turn symbol) for two selected curves. The first-look distance (longitudinal distance measured from the sign to a driver's eyes at which a driver foveally fixates the sign for the first time), last-look distance (the distance measured from the sign to a driver's eyes where he or she moves the eyes away from the sign for the last time before reaching the sign), number of looks and durations of looks at the warning sign were of main interest in this study. Cumulative last-look distance, first-look duration, and last-look duration graphs were established. The results of this study and a previous similar study indicate that drivers look on the average about two times at a warning sign during a nighttime low-beam approach. It was found that between the first look (information acquisition) and the last look (confirmation) at a sign there was usually at least one eye fixation on the roadway ahead. Using cumulative eye fixation duration data obtained for straight road driving under low-beam nighttime conditions published in another study and an average saccade duration of about 0.03 sec, a sign reading distance model was developed that determines the distance (minimum required legibility distance, MRLD) at which a simple bold symbol on a warning sign must be recognized. The model provides for a given speed the overall cumulative probability distribution function for the MRLD in terms of distance or in terms of time. The advantage of this model, which is applicable to warning signs with simple symbols under low-beam illumination at night, is that it is totally based on observed, recorded, and analyzed driver eye scanning and information-seeking behavior in the field.


  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 140-146
  • Monograph Title: Traffic control devices, visibility, and railroad grade crossings
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00714889
  • Record Type: Publication
  • ISBN: 0309061601
  • Files: TRIS, TRB
  • Created Date: Dec 12 1995 12:00AM