NEW DIRECTIONS IN ROADWAY LIGHTING

The American National Standard Practice for Roadway Lighting (8 July 1977), prepared by the Illuminating Engineering Society (IES), is described. Also mentioned is the Commission Internationale d'Eclairage standard practice, which expresses lighting level requirements in terms of roadway luminance rather than illuminance, the basis of the IES standard. An illuminance- and a luminance-based system are compared. While illuminance measures the amount of light provided by the lighting system, the eye sees only the reflected portion (luminance). The luminance method provides the lighting engineer with a better understanding of the ultimate appearance of a scene, although it does not deal with the lighting of vertical surfaces. The current IES Standard Practice, when revised in 1982, is expected to replace luminance with illuminance as the design criterion. The calculation procedure for luminance is presented, a methodology for mathematically predicting the luminance intensity and distribution during the design process. The contrast of an object with its background is discussed, with particular reference to the Visibility Index, a contrast-based set of recommendations under consideration for IES adoption which require the calculation of vertical illumination. Under this proposed method, a given contrast level can often be satisfied by an object which is either brighter or less bright than the pavement. Appended are a discussion of pavement reflectance values and their calculation including r-tables for four pavement classes (reflective characteristics); derivation of luminance equations; and calculations for disability glare (veiling luminance) and its effects on visibility.

• Supplemental Notes:
  • Technology Sharing Program. Sponsored by Federal Highway Administration.
• Corporate Authors:

  Franklin Institute

  20th and Benjamin Franklin Parkway
  Philadelphia, PA  United States  19103
• Authors:
  • Gallagher, V P
• Publication Date: 1980

Media Info

• Features: References;
• Pagination: 34 p.

Subject/Index Terms

• TRT Terms: Calculation; Glare; Illuminating engineering; Luminosity factor; Pavements; Reflection; Standards; Street lighting; Visibility
• Uncontrolled Terms: Computation
• Old TRIS Terms: Illumination engineering; Luminosity
• Subject Areas: Highways; Pavements; Safety and Human Factors;

Filing Info

• Accession Number: 00385635
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: FHWA-TS-80-223, HS-029 103
• Files: HSL, USDOT
• Created Date: Jun 28 1984 12:00AM