Crash Modification Factors (CMFs) for Automated Traffic Signal Performance Measures (ATSPMs)

Automated traffic signal performance measures (ATSPMs) offer an alternative approach to traditional signal retiming. They are developed using second-by-second data that can be collected over several months or years. The Federal Highway Administration (FHWA) included ATSPMs in Every Day Counts 4, and since then, dozens of agencies have installed this new technology. ATSPMs have been shown to help agencies improve operations at signalized intersections through reduced split failures, arrivals on red, red-light running, and delay. The right-of-way time that is allocated to different modes and movements can significantly impact behavior–drivers willing to take smaller gaps, pedestrians waiting for the walk signal, or bicyclists clearing an intersection. While not a true adaptive solution, ATSPMs give agencies the opportunity to make near-real-time adjustments based on data from the field. There has been previous research on the safety impacts of Adaptive Signal Control Technology (ASCT), but the same level of research has not been completed for ATSPMs. This research would quantify reductions in crash frequency and severity resulting from the deployment of ATSPM signal retiming. It would inform public agencies about the safety benefits and help them make funding decisions related to ATSPM systems. The objectives of this research are to (1) identify and organize ATSPM signal retiming and/or associated operational improvements with respect to site characteristics (e.g., geometry, volumes, etc.), (2) quantify crash modification factors and/or functions associated with ATSPM signal retiming (for all modes for specific conflict types and severity) at a quality that could facilitate inclusion in the Highway Safety Manual or Crash Modification Factors Clearinghouse, (3) develop guidance for the use of ATSPM signal-retiming-related CMFs, and (4) document case study costs and benefits associated with safety improvements resulting from ATSPM signal retiming (expanding on information in FHWA-HOP-20-003).


  • English


  • Status: Proposed
  • Funding: $400000
  • Contract Numbers:

    Project 17-109

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Harrigan, Edward

  • Start Date: 20211122
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01773426
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-109
  • Files: TRB, RIP
  • Created Date: May 24 2021 3:14PM