Estimating Effectiveness of Safety Treatments in the Absence of Crash Data

Crash modification factors (CMFs) and functions are developed from historic crash data and help safety professionals estimate the expected safety impacts of specific roadway treatments. There has been a significant amount of research to develop CMFs for common safety strategies and many are included in the AASHTO Highway Safety Manual (HSM) and Federal Highway Administration (FHWA) CMF Clearinghouse. However, there are many instances in which developing reliable CMFs with conventional crash-based evaluations may not be practical or possible. For example, using crash data to evaluate innovative intersection designs or new traffic control strategies requires multiple years of data collection to accumulate a sufficient number of installations and crash history. Additionally, countermeasures that improve safety for crash types such as bicycle, pedestrian or other vulnerable road user crashes, are often lacking in quality CMFs because crash data is limited or not available. Research is needed to develop and apply new methods for developing CMFs or other quantifiable measures of safety for these cases, such as conflicts, speed changes, and lane deviations. The objective of this project was to develop a procedural guide for using alternative measures of safety in the absence of crash data for developing crash modification factors and functions and other quantifiable measures in the absence of crash data. The new measures were to be evaluated against established crash-based measures. In addition, it was expected that the new measures of safety developed would span a range of site conditions, crash types and severity. The procedural guide is to support informed decision making during project planning, project development, and other road safety management activities and include several use case studies.


  • English


  • Status: Completed
  • Funding: $600000
  • Contract Numbers:

    Project 17-86

  • Sponsor Organizations:

    National Cooperative Highway Research Program

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

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Jared, David

  • Performing Organizations:

    Vanasse Hangen Brustlin, Incorporated

    333 Fayetteville Street, Suite 1450
    Raleigh, NC  United States  27601
  • Principal Investigators:

    Porter, Richard

  • Start Date: 20181022
  • Expected Completion Date: 20230331
  • Actual Completion Date: 20230331
  • Source Data: RiP Project 41640

Subject/Index Terms

Filing Info

  • Accession Number: 01634971
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-86
  • Files: TRB, RIP
  • Created Date: May 19 2017 9:39AM