ADOT State-Specific Crash Prediction Models: An Arizona Needs Study

The predictive method in the Highway Safety Manual (HSM) includes a safety performance function (SPF), crash modification factors (CMFs), and a local calibration factor (C), if available. Two alternatives exist for applying the HSM prediction methodology to local conditions. They are either calibration of the SPFs found in the HSM or the development of jurisdiction-specific SPFs The objective of this study was to develop a process to evaluate the SPFs contained in the HSM for road segments and intersections on the Arizona State Highway System and to determine if those SPFs should be calibrated or if Arizona-specific SPFs should be developed. The recommendations are that Arizona Department of Transportation (ADOT) move forward with SPF calibration for all HSM safety performance functions as for project-level safety analysis in Arizona. A specific calibration function has been calculated for two-lane rural undivided highways. Safety analysis is progressing at a promising rate and can be used to attain significant reductions in fatal crashes and crash severity. To achieve this, ADOT will need to make a significant commitment to developing and maintaining a comprehensive database of roadway characteristics combined with crash data and average annual daily traffic volume data that are all linked through a common linear referencing system.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; References; Tables;
  • Pagination: 212p

Subject/Index Terms

Filing Info

  • Accession Number: 01633244
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-AZ-16-704
  • Contract Numbers: SPR 000-1(181) 704
  • Created Date: Apr 28 2017 10:42AM