Effect of Lighting on Safety in Utah Roadways

According to the Utah Department of Transportation (UDOT) crash database, 37% of traffic fatalities occur at night. Roadway lighting has been widely used as a countermeasure for nighttime crashes. This countermeasure is based on research that has been completed simply on a binary flag on whether lighting exists or not. The current method to determine the effects of lighting on roadway safety is to apply the crash modification function/factor (CMF) from the Highway Safety Manual by taking lighting information as a binary variable. However, this value has not been developed for the quality of lighting, nor has it been developed for Utah. In Utah, the evaluation of lighting quality effects on roadway safety is limited by a few factors including limited information on lighting inventory, methods of lighting choices and placement, and limited data on the quality of lighting. Due to the limited data on the lighting quality and locations, it is difficult to associate the effects of lighting on roadway safety. Decisions on the location and the type of lighting are not currently associated with roadway safety, but come from standard drawings, as UDOT currently does not have a specific guideline that is optimized to reduce nighttime crashes. There is a need for research to help UDOT develop more optimized lighting designs (not necessarily higher level of lighting) at different roadway settings on surface streets to reduce nighttime crashes. The objective of this research is to find the correlation between nighttime crashes and lighting metrics to develop a definition for different levels of lighting (well-lit, moderately- lit, low-lit) in relation to safety. Lighting metrics include vertical and horizontal illuminance, intensity of lighting at the pavement level (illuminance), and lighting uniformity. Based on this correlation, the research team will develop a crash modification function/factor (CMF) for lighting specific to Utah roadways.


    • English


    • Status: Active
    • Funding: $70000
    • Contract Numbers:


    • Sponsor Organizations:

      Utah Department of Transportation

      Research and Innovation Division
      Salt Lake City, UT  United States  84114
    • Managing Organizations:

      Utah Department of Transportation

      Research and Innovation Division
      Salt Lake City, UT  United States  84114
    • Project Managers:

      Jensen, Travis

    • Performing Organizations:

      Avenue Consultants, Incorporated

      6575 South Redwood Road,. Suite 101
      Taylorsville, UT  United States  84123
    • Principal Investigators:

      Bassett, David

    • Start Date: 20221216
    • Expected Completion Date: 20240630
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01874621
    • Record Type: Research project
    • Source Agency: Utah Department of Transportation
    • Contract Numbers: 238591
    • Files: RIP, STATEDOT
    • Created Date: Feb 26 2023 10:07PM