Highway Safety Manual Applied in Missouri – Freeway/Software

The American Association of State Highway and Transportation Officials' (AASHTO’s) Highway Safety Manual (HSM) facilitates the quantitative safety analysis of highway facilities. In a 2014 supplement, freeway facilities were added to the original HSM manual which allows the modeling of highway interchanges. This report documents the calibration of the most vital freeway interchange facility types in Missouri. These facility types include nine freeway interchange terminals, including diamond, partial cloverleaf, and full cloverleaf interchanges. The non-terminal facilities included entrance and exit speed-change lanes, and entrance and exit ramps. The calibrated facilities applied to both rural and urban locations. For each facility type, sample sites were randomly selected from an exhaustive master list. Four types of data were collected for each site: geometric, annual average daily traffic (AADT), traffic control, and crash. Crash data was especially noteworthy because of the crash landing problem, i.e. crashes were not located on the proper interchange facility. A significant companion crash correction project was undertaken involving the review of 12,409 crash reports, and the detailed review of 9,169 crash reports. Using the corrected data, 44 calibration values were derived for freeway terminal and non-terminal facilities. These values are the first reported freeway interchange calibration values since the release of the 2014 HSM supplement.

  • Record URL:
  • Record URL:
  • Supplemental Notes:
    • Report date: March 2016; published June 2016.
  • Corporate Authors:

    University of Missouri, Columbia

    Department of Civil and Environmental Engineering
    Columbia, MO  United States  65211-2200

    Missouri Department of Transportation

    Construction and Materials Division
    P.O. Box 270
    Jefferson City, MO  United States  65102

    Midwest Transportation Center

    2711 South Loop Drive, Suite 4700
    Ames, IA  United States  50010-8664

    Department of Transportation

    Office of Assistant Secretary for Research and Technology
    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Sun, Carlos
    • ORCID 0000-0002-8857-9648
    • Edara, Praveen
    • Brown, Henry
    • Nemmers, Charles
    • Claros, Boris
    • Khezerzadeh, Amir
    • Zhang, Mengyuan
    • Nam, Kyoungmin (Andrew)
    • Berry, Jacob
  • Publication Date: 2016-3


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 280p

Subject/Index Terms

Filing Info

  • Accession Number: 01603637
  • Record Type: Publication
  • Report/Paper Numbers: cmr 16-009, MoDOT project# TR201405
  • Contract Numbers: DTRT13-G-UTC37
  • Created Date: Jun 15 2016 8:16AM