IERI PROJECT 85-67: RELATIONSHIP BETWEEN ILLUMINATION AND FREEWAY ACCIDENTS

THE OPTIMUM DESIGN ILLUMINATION LEVEL AND UNIFORMITY NEEDED ON URBAN FREEWAYS, AS RELATED TO ACCIDENT RATES WAS DETERMINED. DATA WERE COLLECTED FROM A WIDE VARIETY OF FREEWAYS, AND COMPARED BY USING THE RATIO OF NIGHT/DAY ACCIDENT RATES PER MILLION VEHICLE MILES. THE TABULATIONS INCLUDED OTHER FACTORS SUCH AS ROADWAY ELEMENTS, WEATHER, DRIVER AGE AND TYPES OF ACCIDENTS. LIGHTED URBAN FREEWAYS HAVE A SIGNIFICANTLY LOWER NIGHT ACCIDENT POTENTIAL THAN UNLIGHTED ONES; AN AVERAGE REDUCTION OF 40 PERCENT IN NIGHT ACCIDENTS CAN BE PREDICTED AS A RESULT OF LIGHTING. THE CALCULATED COST BENEFIT RATIO, USING A 20-YEAR LIGHTING AMORTIZATION, WAS FOUND TO BE 2.3 FOR FREEWAYS WITH FOUR LANES, 1.4 FOR SIX LANES, AND 1.7 FOR EIGHT OR TEN LANES. FREEWAYS WITH MEASURED "TYPICAL" IN-SERVICE ILLUMINATION LEVELS BETWEEN 0.3 AND 0.6 HFC (HORIZONTAL FOOTCANDLES) HAD THE BEST ACCIDENT RATE RATIOS; HOWEVER MAINTAINED ILLUMINATION FOUND IN THE LIGHTING SYSTEMS RANGED FROM 28 TO 82 PERCENT OF INITIAL VALUES, WITH AN AVERAGE OF 50 PERCENT. /AUTHOR/

• Supplemental Notes:
  • Vol 66, No 5, PP 365-393
• Authors:
  • Box, P C
• Publication Date: 1971-5

Media Info

• Serial:
  • ILLUMINATING ENGINEERING

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Crashes; Days; Freeways; Light; Night; Street lighting; Urban highways
• Old TRIS Terms: Freeway lighting
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00221372
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 6 1971 12:00AM