MINIMUM PHOTOMETRIC PROPERTIES OF RETROREFLECTIVE SIGNING MATERIALS

Laboratory and field studies were conducted to assess the minimum luminance levels of signs that ensures that they will be detected and identified at adequate distances under nighttime driving conditions. Thirty subjects participated in the field study, driving a car on public roads and reporting when they could identify the test signs that were positioned at random points along the side of the road. Surround complexity, subject age, retroreflective efficiency, and sign color were considered. 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. For example, sign retroreflectivity had to be increased by a factor of about 10 to achieve equivalent conspicuity when going from areas of low to high complexity and by a factor of about 3 to compensate for the effect of subject age. 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 and the rationale for their development are presented for stop signs, construction area warning signs, warning signs, and overhead guide signs.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1989/1247/1247-008.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=MINIMUM+PHOTOMETRIC+PROPERTIES+OF+RETROREFLECTIVE+SIGNING+MATERIALS&author=P.+Olson&publication_year=1989
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309049725
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1247, Visibility Criteria for Signs, Signals, and Roadway Lighting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Olson, Paul L
• Conference:
  • Symposium on Visibility Criteria for Signs, Signals, and Roadway Lighting, 1988, Minneapolis, Minnesota, USA
• Publication Date: 1989

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: p. 56-68
• Monograph Title: Visibility criteria for signs, signals, and roadway lighting
• Serial:
  • Transportation Research Record
  • Issue Number: 1247
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Color; Expected value; Field tests; Human subject testing; Laboratory tests; Luminous intensity; Materials; Night; Overhead traffic signs; Photometry; Recommendations; Retroreflectivity; Stop signs; Traffic signs; Visibility; Warning signs; Work zone traffic control
• Old TRIS Terms: Expectation; Traffic sign materials
• Subject Areas: Highways; Materials; Operations and Traffic Management; Research; Safety and Human Factors; I73: Traffic Control;

Filing Info

• Accession Number: 00495505
• Record Type: Publication
• ISBN: 0309049725
• Files: TRIS, TRB, ATRI
• Created Date: Jul 31 1990 12:00AM