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Minimum requirements for adequate nighttime conspicuity of highway signs

File Language:
English


Details

  • Creators:
    Olson, Paul L.
  • Corporate Creators:
    University of Michigan. Transportation Research Institute
  • Subject/TRT Terms:
  • Publication/ Report Number:
  • Resource Type:
    Tech Report
  • Geographical Coverage:
    United States
  • Edition:
    Final report; Sep 1985-Dec 1987
  • Corporate Publisher:
    University of Michigan. Transportation Research Institute
  • NTL Classification:
    AGR-SAFETY AND SECURITY-SAFETY AND SECURITY ; NTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATION ; NTL-SAFETY AND SECURITY-Highway Safety
  • Abstract:
    A laboratory and field study were conducted to assess the minimum luminance levels of signs to ensure that they will be detected and identified at adequate distances under nighttime driving conditions. A total of 30 subjects participated in the field study, driving a car on public roads, and reporting when they could identify the test signs, which were positioned at random points along the side of the road. Variables considered were: surround complexity, subject age, retrorefective efficiency, and sign color. A study was also carried out to measure the effect of subject expectancy. All of the independent variables, including color, were found to have an effect on sign conspicuity. The colors red, orange, green, and blue had substantially greater conspicuity than did yellow with equivalent retroreflectivity. Possible reasons for the latter finding are discussed. Minimum retroreflectivity recommendations are presented for stop signs, construction area warning signs, warning signs, and overhead guide signs, together with the rationale for their development.
  • Format:
    PDF
  • Collection(s):
  • Main Document Checksum:
    urn:sha256:cf8b66f0e186dd3f6af3b24bdd492e536ddbd89d70874e09bc4720fa360c4cc7
  • Download URL:
  • File Type:
    Filetype[PDF - 3.11 MB ]
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