CONTINOUS FREEWAY ILLUMINATION

WHETHER CONTINUOUS FREEWAY LIGHTING IS EFFECTIVE IN REDUCING NIGHTTIME ACCIDENT OCCURRENCE IS DETERMINED. BASICALLY THREE METHODS OF ATTACK WERE USED. THESE WERE: (1) DETERMINING AND COMPARING THE RATIO OF THE NUMBER OF DAY TO NIGHTTIME ACCIDENTS OF TWO ILLUMINATED FREEWAYS VERSUS THESE RATIOS ON NONILLUMINATED FREEWAYS. (2) COMPARING THE HOLLYWOOD FREEWAY WHICH IS ILLUMINATED WITH THE HARBOR FREEWAY WHICH IS NOT ILLUMINATED. AND (3) COMPARING ACCIDENTS OCCURRING BETWEEN 5 AND 7 PM IN JUNE WHICH IS DAYLIGHT VERSUS ACCIDENTS OCCURRING BETWEEN THE SAME HOURS IN DECEMBER WHICH IS DARK. THE EVIDENCE UNCOVERED BY THIS STUDY REGARDING THE BENEFITS OF CONTINUOUS FREEWAY ILLUMINATION ARE BOTH CONFLICTING AND INCONCLUSIVE. THIS MAY BE THE CASE BECAUSE THE BENEFITS OF ILLUMINATION ARE IN FACT MARGINAL OR BECAUSE THE STUDY METHODS ARE NOT THE PARAMETERS THAT SHOULD BE USED IN A STUDY OF THE NATURE. THE SPACING OF THE ELECTROLIERS AND SIZE OF THE LAMPS USED PROVIDE A CALCULATED INITIAL ILLUMINATION LEVEL OF OVER ONE FOOTCANDLE AVERAGE. THE ACTUAL ILLUMINATION LEVELS AS OBTAINED FROM FIELD MEASUREMENTS RANGE FROM 0.20 TO 0.35 FOOTCANDLES AVERAGE. THESE LEVELS ARE CONSIDERABLY LESS THAT THE 0.6 FOOTCANDLE LEVEL OF AVERAGE MAINTAINED ILLUMINATION CONSIDERED ADEQUATE FOR CONTINUOUS LIGHTING FOR FREEWAYS BY THE AASHO "AN INFORMATIONAL GUIDE FOR LIGHTING CONTROLLED ACCESS HIGHWAYS". IT IS NOT KNOWN WHETHER OR NOT A HIGHER LEVEL OF ILLUMINATION WOULD RESULT IN ACCIDENT BENEFITS. /SRIS/

  • Supplemental Notes:
    • 36 Pp, 15 TAB, 3 FIG
  • Corporate Authors:

    California Division of Highways

    Bridge Department
    Sacramento, CA  USA  05914
  • Publication Date: 1965-5

Subject/Index Terms

Filing Info

  • Accession Number: 00220838
  • Record Type: Publication
  • Source Agency: Nat Safety Council Safety Res Info Serv
  • Files: TRIS
  • Created Date: Nov 23 1970 12:00AM