Enhancement of Roadside Design Safety Prediction Models for the Highway Safety Manual

The objectives of this research are to (a) validate roadside safety performance functions (SPF) and associated crash modification factors (CMF) developed in NCHRP Project 17-54, including associated design element variables, that are appropriate for consideration by AASHTO to incorporate in the Highway Safety Manual, (b) develop or enhance roadside SPFs to supplement or replace existing models for rural, suburban, or urban arterial roadways with consideration of total versus single vehicle crashes and their frequency and severity, and (c) coordinate the research products with planned content of other performance-based design manuals such as the Green Book and Roadside Design Guide. The research results shall be used to develop proposed draft language for consideration by AASHTO to incorporate the research findings in appropriate HSM chapters. The work will include review of available roadway and roadside design element inventory and associated crash data and the potential collection of new data. Both the roadway departure SPFs and related CMFs for design elements will be provided for the roadway facility types prioritized by AASHTO based on available or collected data. This research shall (a) coordinate with current NCHRP Projects 17-82, “Proposed Guidance for Fixed Objects in the Roadside Design Guide,” 17-85, “Development and Application of Crash Severity Models for the Highway Safety Manual,” 17-88, “Roadside Encroachment Database Development and Analysis,” and 17-92, “Developing Safety Performance Functions for Rural Two-Lane Highways that Incorporate Speed Measures,” and (b) consider the results of completed NCHRP Project 15-65, “Development of Safety Performance Based Guidelines for the Roadside Design Guide,” NCHRP Web-Only Document 296: Guidelines for Cost-Effective Safety Treatments of Roadside Ditches, NCHRP Research Report 911: Guidelines for Traversability of Roadside Slopes, and associated projects.


  • English


  • Status: Active
  • Funding: $500000
  • Contract Numbers:

    Project 17-104

  • 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:

    Barcena, Roberto

  • Performing Organizations:

    University of North Carolina, Chapel Hill

    Chapel Hill, NC  United States  27514
  • Principal Investigators:

    Srinivasan, Raghavan

  • Start Date: 20220906
  • Expected Completion Date: 20250305
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01773412
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-104
  • Files: TRB, RIP
  • Created Date: May 27 2021 7:30PM