A LUMINANCE APPROACH TO HIGHWAY SIGN LIGHTING

THE WORK REPORTED IN THIS PAPER IS CONCERNED WITH DESIGNING FOR THE VISIBILITY OF HIGHWAY SIGNS USING A LUMINANCE OR REFLECTED LIGHT. THE NATURE OF THE PROBLEM IS DEFINED AND THE DEVELOPMENT OF LUMINANCE SPECIFICATIONS IS DISCUSSED. THE CONDITIONS OF AVERAGE LUMINANCE LEVEL ARE OUTLINED. THE LUMINANCE LEVEL NECESSARY TO CREATE A VISIBILITY REVERSAL WILL BE DEPENDENT UPON THE EYE'S ADAPTATION STATE, AND THEREFORE WILL BE RELATED TO THE AMBIENT LIGHTING LEVEL. SUGGESTED AVERAGE LUMINANCE LEVELS ARE TABULATED. FURTHER RESEARCH IN THIS AREA IS DESIRABLE. THE DEVELOPMENT OF A PRACTICAL APPROACH REQUIRES PRECISE INFORMATION ON THE REFLECTANCE CHARACTERISTICS OF VARIOUS SIGN FACE MATERIALS. DETAILS ARE GIVEN OF REFLECTANCE CHARACTERISTICS OF HIGHWAY SIGNS. A VISUAL TASK PHOTOMETER WAS USED TO DETERMINE BIDIRECTIONAL REFLECTANCE VALUES. TYPICAL REFLECTANCE RESULTS ARE ILLUSTRATED. THE PROVISION OF PERFECTLY UNIFORM ILLUMINATION FOR ANY RETRO-REFLECTING SIGN FACE MATERIAL, WILL CREATE A NON-UNIFORM LUMINANCE PATTERN. THREE PROBLEM AREAS ON THE SIGN FACE ARE IDENTIFIED, AND A METHOD OF APPROACH TO THESE PROBLEMS IS SUGGESTED. A MATHEMATICAL EQUATION FOR DETERMINING THE DESIGN CANDLEPOWER IN ANY DIRECTION FOR UNIFORM LUMINANCE IS PRESENTED.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00994480
• Corporate Authors:

  Illuminating Engineering Society

  120 Wall Street, 17th Floor
  New York, NY  United States  10005-4001
• Authors:
  • Lewin, I
• Publication Date: 1974-1

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 122-8
• Serial:
  • Illuminating Engineering Society, Journal of
  • Volume: 3
  • Issue Number: 2
  • Publisher: Illuminating Engineering Society
  • ISSN: 0099-4480

Subject/Index Terms

• TRT Terms: Equations; Lighting; Luminescence; Luminous materials; Materials; Reflectivity; Specifications; Traffic signs; Visibility; Visual perception
• Uncontrolled Terms: Reflectance
• Old TRIS Terms: Luminous sign
• Subject Areas: Highways; Materials; Safety and Human Factors;

Filing Info

• Accession Number: 00222347
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 15 1974 12:00AM