Development and Application of Crash Severity Models for the Highway Safety Manual

The objectives of this project are to: (1) assess the current HSM approaches to severity estimation and prediction using SPFs; (2) Identify gaps and opportunities in the current severity prediction/estimation procedures within the HSM; (3) Develop and validate new severity models to address the gaps and opportunities; and (4) develop a guidance document that includes protocols for the use and application of severity based models in a format suitable for possible adoption in the HSM. The guidance and protocols should address: (1) Both the current HSM methods and any newly created models that consider, but are not limited to the following potential approaches: (a) Number of crashes at each severity level by predicating total crash count and adjusting by assumed or observed crash severity distribution. (b) Number of crashes at each severity level by predicting crashes for each of the individual severity categories. (c) Estimated probability of crashes at each severity level. (d) Number of crashes at each severity level by predicting both the total crashes and the crash severity likelihoods. (2) How crash frequency and severity models would be integrated. (3) New crash models shall include but are not limited to discrete choice models. (4) Statistical reliability in terms of, but not limited to, spatial, temporal, and statistical specification and fit. (5) Data quality and availability and how each affects the models application at both the national and local levels. (6) The criteria for model development and selection. (7) The use of the models for network screening (HSM Part B) and predictive methods (HSM Part C). (8) How project planning and design decisions are affected by different modeling approaches. (9) The performance of the models at varying AADTs, segment lengths, roadway functional classes, and contexts (e.g. roadside conditions, and speeds). The guidance should include a number of case studies or illustrative examples that demonstrate the issues with model use and statistical reliability. In addition, the guidelines should promote better informed planning decisions and the use of engineering judgment in the model application, greater implementation of crash prediction models, and better acceptance of model results leading to improved decision making.


  • English


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

    Project 17-85

  • 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:

    University of Connecticut, Storrs

    Storrs, CT  United States  06268-5202
  • Principal Investigators:

    Ivan, John

  • Start Date: 20181115
  • Expected Completion Date: 20220630
  • Actual Completion Date: 0
  • Source Data: RiP Project 41639

Subject/Index Terms

Filing Info

  • Accession Number: 01634970
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-85
  • Files: TRB, RIP
  • Created Date: May 19 2017 1:00AM