A VISIBILITY METRIC FOR SAFE LIGHTING OF CITY STREETS

Field experiments were conducted to determine the time-separation gap required by unalerted drivers to respond evasively to a visual problem of known photometric characteristics. Through these experiments a data base was established from which a method for defining the visibility requirements for safe braking performance was developed. This method involves determination of the Visibility Index and measurement of driver performance by Time-To-Target (the theoretical intercept time based on the measured velocity and the separation distance at the time of the evasive maneuver). The method yields a graph from which a determination of minimum visibility requirements can be made, given a known design speed and an arbitrarily selected deceleration rate for design purposes. /HRIS/

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  • Supplemental Notes:
    • Presented at the Annual IES Conference, July 13-17, 1975, San Francisco, Calif.
  • Corporate Authors:

    Illuminating Engineering Society

    120 Wall Street, 17th Floor
    New York, NY  United States  10005-4001
  • Authors:
    • Gallagher, V P
  • Publication Date: 1976-1

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Filing Info

  • Accession Number: 00129601
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 21 1976 12:00AM