Enhancing Highway Safety Manual Guidance on Pedestrian and Bicyclist Countermeasures (CMF/SPF Development)

The AASHTO Highway Safety Manual (HSM), first edition, provides analytic tools and techniques for estimating effects of changes to the roadway environment on motor vehicle crashes, but provides almost no information about effects on pedestrian and bicyclist crash frequency. NCHRP Project 17-84, “Pedestrian and Bicycle Safety Performance Functions for the Highway Safety Manual,” is in the process of developing crash modification factors (CMFs) and safety performance functions (SPFs) for pedestrians and bicyclists in support of a future HSM, second edition (see Special Note L below). However, the safety benefits of many pedestrian and bicycle countermeasures, especially newer  treatments, will still be unknown after completion of NCHRP Project 17-84. Furthermore, established CMFs focused on vehicle-vehicle collisions do not properly account for effects on pedestrian and bicyclist crash outcomes. The objectives of this research are to (1) develop CMFs and SPFs related to pedestrian and/or bicyclist safety countermeasures and (2) assess pedestrian and/or bicyclist safety outcomes associated with vehicle safety countermeasures.   PHASE I Task 1. Compile and review findings and recommendations from previous research and countermeasure implementation activities. Task 2. Identify research priorities to be addressed in Phase II for (1) developing CMFs and SPFs for pedestrian and/or bicyclist safety countermeasures and (2) pedestrian and/or bicyclist safety outcomes associated with vehicle safety countermeasures. Task 2.2 is anticipated to focus on high-priority countermeasures not addressed by NCHRP Research Report 992: Guide to Pedestrian Analysis or NCHRP Web-Only Document 318: Safety Prediction Models for Six-Lane and One-Way Urban and Suburban Arterials. If necessary, propose new methodologies to predict pedestrian and/or bicyclist safety outcomes. Task 3. Develop a data collection and analysis plan (including surrogate safety measures) for conducting new research in Phase II. The plan should aim to develop CMFs and SPFs, in Phase II, with adequate ratings to support eventual inclusion in the HSM and to support performance-based practical design. Task 4. Prepare an Interim Report that documents the work completed in Tasks 1 through 3. Update the work proposed for Phase II. PHASE II Task 5. Collect data and conduct data analysis according to the approved Interim Report to achieve the research objectives. The findings should consider safety impacts on all vulnerable road users, including those with vision or mobility impairments. Task 6. Prepare and submit a draft final report. Task 7. Conduct implementation activities, including (1) prepare draft language for consideration by AASHTO to incorporate the research results into the next update of the HSM (herein called AASHTO Deliverable); (2) participate in a webinar hosted by TRB to share draft findings with a large group of stakeholders, and collect stakeholder feedback for use in finalizing the deliverables; (3) develop outreach materials to support practitioners’ understanding and implementation of the research findings; and (4) propose parameters for conducting pilot tests to apply CMFs and SPFs developed by this project. Task 8. Final deliverables should include (1) a final research report documenting the entire research effort and findings; (2) AASHTO Deliverable; (3) outreach materials to support practitioners’ understanding and use of the research findings; (4) prioritized recommendations for future research; (5) presentation material; and (6) a technical memorandum on implementation.


  • English


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

    Project 17-112

  • 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:

    Retting, Richard

  • Principal Investigators:

    Zhao, Yi

  • Start Date: 20230725
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01846130
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-112
  • Files: TRB, RIP
  • Created Date: May 23 2022 4:28PM