DETERMINE THE LUMINOUS REQUIREMENTS FOR RETROREFLECTIVE HIGHWAY SIGNING

This research effort which investigated the effect of reflectivity on sign legibility, addressed several specific questions: what is the range of acceptable legend and/or background luminosity for effective signing? How does this range vary as a function of sign characteristics, road geometry, and environmental conditions? Can an optimum luminosity be specified for each situation? When, according to luminosity criteria, should a sign be replaced? The study used a laboratory simulation validated by a field study. Findings regarding predictive legibility curves, selection of signing materials, effects of sign position, correction for stream traffic effects, and corrections for background color are detailed. It was found that sign legibility is determined by a number of factors among the most important of which are the luminance characteristics. Although highly reflective sign backgrounds have the potential of providing somewhat greater legibility distance than nonreflective or moderately reflective backgrounds, any background material is capable of yielding satisfactory legibility distance. Findings regarding signs with white legends, black backgrounds, black legends, background color, surround luminance, and differences in people's ability to read highway signs are outlined.

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• Corporate Authors:

  Transportation Research Board

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  Washington, DC  United States  20001
• Authors:
  • Olson, P
  • Bernstein, A
• Publication Date: 1977

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 158-166
• Serial:
  • NCHRP Summary of Progress
  • Publisher: Transportation Research Board

Subject/Index Terms

• TRT Terms: Distance; Environment; Forecasting; Highway design; Human factors; Legibility; Luminosity factor; Retroreflection; Signs; Simulation; Symbols; Traffic flow; Traffic signs
• Uncontrolled Terms: Background (Traffic signs); Sign legend
• Old TRIS Terms: Luminosity; Retrodirective reflection
• Subject Areas: Geotechnology; Highways; Materials; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 00170827
• Record Type: Publication
• Report/Paper Numbers: Project 3-24-Fy'75
• Files: TRIS, TRB
• Created Date: Jul 19 1978 12:00AM