Crash Reduction Factors for Traffic Engineering and ITS Improvements

The objective of this project is to develop reliable Crash Reduction Factors (CRFs) for traffic engineering, operations, and Intelligent Transportation Systems (ITS) improvements. Reliable CRFs, at a minimum, meet the following criteria: (1) The CRFs are methodologically and statistically valid. Expert judgment is not a substitute for rigorous analysis. Separate values for CRFs (or a method for adjusting the CRFs) are tabulated that account for various influencing factors such as the highway facility, operating condition, weather, time of day, percentage of truck traffic, and pre-existing crash history as appropriate. (2) The applicability of the CRF is known and documented. For example, some CRFs may denote an impact on crashes only at a specific location whereas other CRFs may affect crashes for an entire stretch of roadway, or some CRFs may apply only to specific accident types or to specific pre-existing conditions (e.g., high percentages of wet weather crashes). (3) The CRFs reflect improvements or combinations of improvements that are of interest to Departments of Transportation (DOTs.) Such improvements could, for example, include (i) adding a centerline rumble strip, (ii) modifying a signal in conjunction with adding a left-turn lane or (iii) increasing the frequency of a safety service patrol in concert with improved variable message sign (VMS) signing. (4) The CRFs should represent the different crash categories that reflect the impact of the improvement. Crash categories might include total crashes, severe injury crashes, property damage only crashes, and specific crash types (such as rear end and angle). (5) The CRFs reflect variability. The best estimate of the CRFs, along with some technique that reflects their variability (such as ranges, confidence intervals, standard deviation, or some other technique) should be presented.


  • English


  • Status: Completed
  • Funding: $550000.00
  • Contract Numbers:

    Project 17-25

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Niessner, Charles

  • Performing Organizations:

    University of North Carolina, Charlotte

    Highway Safety Research Center
    Charlotte, NC  United States  27190
  • Principal Investigators:

    Harkey, David

  • Start Date: 20030801
  • Expected Completion Date: 0
  • Actual Completion Date: 20080229
  • Source Data: RiP Project 8581

Subject/Index Terms

Filing Info

  • Accession Number: 01460852
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 17-25
  • Files: RiP, USDOT
  • Created Date: Jan 3 2013 1:33PM