NIGHT-TIME LEGIBILITY OF TRAFFIC SIGNS: CONDITIONS ELIMINATING THE EFFECTS OF DRIVER AGE AND DISABILITY GLARE

The effects of observer age and environmental glare on night-time legibility of traffic signs were investigated in two field experiments with the subjects driving or riding in a car towards a sign. Experiment 1 showed that equating older and younger subjects in terms of their luminance/high contrast visual acuity resulted in elimination of any age effects on legibility. Furthermore, the presence of a glare source with an illuminance of 0.17 or 0.017 lux offset 2 degrees from the sign legend improved legibility distance significantly. The results of experiment 2 indicated that a glare source with an illuminance of 0.0098 lux had no effect on legibility when presented at an offset angle of 1.5 degrees or 0.6 degrees, but it had a significant detrimental effect at an offset angle of 0.2 degrees. The present findings suggest that (1) the usually observed age-related performance decrement on night-time legibility tasks is the result of visual-acuity deficits, and not shortcomings in information-processing ability; (2) legibility is relatively unaffected by glare, unless the glare angle is very small or glare level very high; and (3) glare sources positioned outside of the fovea might improve night-time legibility performance under certain conditions. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00014575
• Corporate Authors:

  Pergamon Press, Incorporated

  Headington Hill Hall
  Oxford OX30BW,    
• Authors:
  • Sivak, M
  • Olson, P L
• Publication Date: 1982-4

Media Info

• Features: References; Tables;
• Pagination: p. 87-93
• Serial:
  • Accident Analysis & Prevention
  • Volume: 14
  • Issue Number: 2
  • Publisher: Elsevier
  • ISSN: 0001-4575
  • Serial URL: http://www.sciencedirect.com/science/journal/00014575

Subject/Index Terms

• TRT Terms: Age; Angularity; Brightness; Drivers; Glare; Legibility; Luminance; Night; Night visibility; Traffic signs; Vision
• Uncontrolled Terms: Angles; Driver age
• Old TRIS Terms: Driver vision
• ITRD Terms: 1757: Age; 6427: Angle; 1772: Driver; 1677: Glare; 540: Legibility; 525: Luminance; 9052: Night; 553: Traffic sign; 2066: Vision
• Subject Areas: Highways; Safety and Human Factors; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 00361668
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Report/Paper Numbers: HS-033 045
• Files: HSL, ITRD, TRIS
• Created Date: Jul 30 1982 12:00AM