Practitioner's Application Guide to the Highway Safety Manual

The Highway Safety Manual (HSM) is a guidance document for incorporating quantitative safety analysis in highway transportation project planning and development processes. Many procedures contained in the HSM are complex and challenging for the average practitioner to apply. Given the complexities of the HSM, it may not be used to its full potential or, in some cases, misapplied by state and local highway agencies. Under NCHRP Project 17-50, “Lead States Initiative for Implementing the Highway Safety Manual,” a Highway Safety Manual User Guide was developed for the 2010 AASHTO HSM, first edition. The NCHRP Project 17-50 guide gave the HSM user a perspective on how to use the HSM. It further addressed a limited set of potential HSM applications, emphasizing how to use the HSM within a safety analysis. However, it has become dated, especially considering the forthcoming HSM section edition (HSM-2). The examples supplied lack detail to address the complex computations and complexities presented in the HSM-2. A vigorous in-depth practitioner guide is proposed to enhance safety professionals' abilities in program management, system planning, project planning, preliminary engineering, final design, construction, maintenance, and operations to address roadway safety for all users and all routes. The objective of this research is to develop a practitioner’s guide on the use of the HSM-2 for system planning, project planning, preliminary engineering, final design, construction, maintenance, and operations applications by identifying proper methods and applications and illustrating them with case studies. The guide should supply practitioners with an understanding of HSM procedures, how to apply the findings, and how to use complex models and multilevel steps to conduct a proper HSM safety analysis and the decision-making process. Discussions within the text should supply practitioners with guidance on interpreting the results, limitations of specific models, and how to decide the proper use and application of model results, along with an understanding of how to apply the results as part of a safety management program. The guide should cover aspects such as, but not limited to: (1) uses of HSM for a broad variety of planning and engineering applications (including different stages, scales, complexities, and system configurations); (2) uses for parts of the HSM (e.g., steps in the safety management process, appropriate use of safety performance functions, adjustment factors, and application of crash modification factors); (3) uses of the HSM in scenario planning or alternative analysis; (4) coordinate use of the HSM with other planning, design, and operations functions (e.g., environmental decisions, capacity analysis, and operations analysis), along with coordination with associated manuals and guides; (5) uses of the HSM in the decision-making process (e.g., network screening, diagnosis, countermeasure selection, economic appraisal of selection, prioritizing projects, and safety effectiveness evaluation); (6) how to consider and incorporate HSM analysis for conditions not implicitly covered by the HSM; (7) uses of the HSM to limit liability and other legal implications of design and operations decisions; and (8) uses of the HSM with associated spreadsheets and freely available software platforms for analyses.


  • English


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

    Project 17-127

  • 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:

    Turner, Anne-Marie

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

Subject/Index Terms

Filing Info

  • Accession Number: 01888640
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-127
  • Files: TRB, RIP
  • Created Date: Jul 25 2023 8:20AM