Factors Contributing to Median Encroachments and Cross-Median Crashes

Cross-median crashes (CMC) frequently result in high severity injuries and fatalities. Cross-median encroachments (CME) are similar events that occur without striking a vehicle in the opposing lane. Although they may not result in comparable injury severities, the seriousness of CMC and CME (CMC&E) events are of equal concern. Studies of contributory factors associated with CMC&E have typically focused on median width, and several have also explored ADT. A few have looked at the influence of geometry and cross sectional elements. Although these studies have been helpful, they do not explore the full range of causal factors. The influence of interchange ramps, interchange spacing, mixture of vehicle types, peak period volumes, peak period duration, land use, posted speed, and the presence of speed transition zones on CMC&E is not well understood. There is also a knowledge gap regarding countermeasures appropriate for the varieties of contributory factors. Understanding when a particular barrier system is and is not appropriate is just as important as knowing that cross-median protection is warranted. Evaluation of contributory factors and injury severities, associated with various countermeasures would provide some insight into which countermeasures to employ to reduce the frequency and severity of these collisions. CMC&E typically occur on the high priority road network and are associated with loss of life, major injuries, user-delay and negative press coverage. Most transportation agencies are placing barrier systems in their highway medians to address CMC&E. For most agencies, these placement decisions are based on median width and ADT. This approach may not be targeting locations with the highest overall risk for CMC&E, leaving correctable locations behind. A successful outcome from this research would lead to better choices about sites to protect and countermeasure selection. Research findings could also be used to identify locations for increased enforcement and other countermeasures. The objective of this research project is to identify statistically significant factors and combinations of factors that influence CMC&E frequency and severity.


  • English


  • Status: Active
  • Contract Numbers:

    Project 17-44

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    American Association of State Highway & Transportation Officials

    444 North Capitol Street, NW, Suite 225
    Washington, DC    20001

    National Cooperative Highway Research Program

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

    Derr, B

  • Performing Organizations:

    Midwest Research Institute

    425 Volker Boulevard
    Kansas City, MO  USA  64110-2299
  • Principal Investigators:

    Graham, Jerry

  • Start Date: 20090306
  • Actual Completion Date: 20110506
  • Source Data: RiP Project 18038

Subject/Index Terms

Filing Info

  • Accession Number: 01464468
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 17-44
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:43PM