The National Academies

NCHRP 17-127 [Pending]

Guide for Applying Quantitative Highway Safety Analysis Methods

  Project Data
Funds: $500,000
Contract Time: 30 months
Staff Responsibility: Anne-Marie Turner


The American Association of State Highway and Transportation Officials (AASHTO) Highway Safety Manual (HSM) is a guidance document for incorporating quantitative safety analysis in highway 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, some practitioners may not use the manual to its full potential. Currently, a new edition of the HSM is in development (HSM-2); this edition will have new and expanded analytical tools. A vigorous and in-depth guide is needed to enhance practitioners’ abilities to use HSM procedures to integrate roadway safety across transportation agency program areas.


The objective of this project is to develop a guide focused on the use and application of quantitative highway safety analysis methods in the HSM-2 for informing decisions throughout the project life cycle, including but not limited to programming, planning, preliminary engineering, final design, construction, maintenance, asset management, assessment of transportation impacts from development, and traffic operations.

The guide will assist practitioners from diverse professional backgrounds and levels of expertise to navigate and properly apply tools in the HSM-2. As a companion document, the guide should use references and not replicate content from the HSM-2.

Accomplishment of the project objective will require at least the following tasks.


PHASE I: Planning for Guide Development

Task 1. A literature review of relevant research related to practitioner application of the HSM. The review shall include published and unpublished research, including a critical analysis of the HSM-2 to identify where additional examples can support practitioner application of HSM procedures.

Task 2. An analysis and synthesis of the results of the literature review to identify the knowledge gaps related to the project objective. These gaps must be addressed in the final product or the recommended future research as budget permits. 

Task 3. A methodology to achieve the project objective to be fully developed in Phase II. At the minimum, the methodology shall incorporate strategies to develop a guide with the following attributes:

  • The appropriate use of the HSM for a broad variety of project stages, scales, complexities, and system configurations;
  • The uses for parts of the HSM (e.g., steps in the safety-management process, the HSM predictive methods, and application of crash modification factors);
  • The use of the HSM in scenario planning, alternative analysis, and performance-based approaches;
  • The use of the HSM to integrate safety performance considerations with other planning, design, and operations functions (e.g., environmental decisions, capacity analysis, and operations analysis), along with coordination with associated manuals and guides;
  • The use of the HSM in the safety-management decision-making process (e.g., network screening, diagnosis, countermeasure selection, economic appraisal of selection, prioritizing projects, and safety-effectiveness evaluation);
  • How to consider and incorporate HSM predictive analysis for roadway and operational conditions that are not addressed by the HSM;
  • The interpretation of results and the role of engineering judgment in HSM analysis (e.g., understanding reliability, communicating results, documentation);
  • The legal considerations for documenting and reporting HSM results (e.g., use of liability neutral engineering language. Please use and refer to NCHRP Legal Research Digest 83: Guidelines for Drafting Liability Neutral Transportation Engineering Documents and Communications Strategies); and
  • The inclusion of case studies and practical examples that present the overall approach and results (instead of step-by-step calculations) while avoiding the use of proprietary tools.

Task 4. A detailed annotated outline for the proposed guide. The outline must include a chapter review schedule with proposed virtual meetings for feedback.

Task 5. An interim report and panel meeting. The interim report must include the analyses and results of completed tasks. The in-person panel meeting will take place after the panel review of the interim report. 


PHASE II: Guide Development

Task 6. Two draft sample chapters, identified by NCHRP, that demonstrate writing style, use of graphics, references, illustrations, case studies, and examples. Contractor may not proceed with guide development until Task 6 has been accepted by NCHRP.

Task 7. A draft guide for applying quantitative safety analysis in highway transportation projects and programs with discussion, case studies, and examples. A virtual panel meeting will take place after the panel review of the draft guide. 

Task 8. A virtual workshop developed and hosted by the contractor with at least 15 representatives of state departments of transportation and other practitioners to review the draft guide. The contractor will revise the draft guide based on feedback gathered during the workshop.  

Task 9. Final deliverables that present the entire research product in a manner that will be useful to practitioners and stakeholders. The final deliverables must include the following:

  • The final guide with draft language and format for consideration by AASHTO;
  • A conduct of research report, including an executive summary, that documents all research and project efforts;
  • A technical memorandum titled “Implementation of Research Findings and Products” (see Special Note K);
  • A PowerPoint presentation with speaker notes suitable for a webinar; and
  • A 90-minute recorded webinar overview of the guide suitable to explain the guide and its contents to practitioners. A draft version of the webinar shall be presented to the panel before recording the final webinar.

STATUS: The contractor has been selected. Contract pending.


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