Light, Medium, and Heavy Rail and Roadway Interface Safety Performance Functions and Crash Modification Factors Development

The Highway Safety Manual (HSM) supplies safety performance functions (SPFs) for several types of roadways and intersections. The CMF Clearinghouse ( supplies crash modification factors (CMFs) that may be applied to determine the effect of various safety countermeasure implementations and activities. One limitation of the HSM is the lack of safety models for highway-rail envelopes (HREs) or consideration of HREs in existing SPFs adjustment factors. For this research problem statement, HRE describes a group of road and rail crossings that include the common highway-rail grade crossing (HRGC) and those interfaces where the railroad track (including light rail transit (LRT) lines) is within and share the travel way with other motorized vehicles or non-motorized users, i.e., pedestrians or bicyclists. HREs are unique facilities that involve two or more transportation modes. There are CMFs contained in the CMF Clearinghouse that cover a variety of safety countermeasures for HRGC. They cover the traditional safety measures, such as signs, bells, gates, lights, and a limited selection of LRT applications, but other CMFs are needed to address gaps for commonly used HRE safety countermeasures. There is a need to have SPFs and additional CMFs to address light rail (transit), medium rail (transit and freight), and heavy rail (transit and freight) HREs. Traditionally researchers have considered safety issues that exist at locations where the rail and the road cross. Complicating the safety issue is that the rail may share the roadway space (e.g., medium/heavy rail within industrial settings and LRT like streetcars), operate parallel along one side of a roadway (at relatively close proximity to the roadway, often in a shared right-of-way), or within the median of a roadway, significantly complicating the operation of the rail and the roadway. These parallel and shared orientations create unique safety concerns that are not well documented and do not have documented CMFs for safety countermeasures that have been implemented. The objective of this research is to develop SPFs and CMFs for all road users (including non-motorized users) that can be used to estimate the severity and number of crashes likely to occur at HREs, under a variety of rural and urban contexts, to include light, medium, and heavy rail HREs. The results of this research should enable transportation agencies to quantify the safety effects of HREs design features and safety performance of implementing countermeasures at a particular location so that safety performance can be compared to alternative configurations. Being able to consider safety effects of these interfaces along with other predicted crashes would aid agencies in finding the safety effectiveness of existing and proposed HREs. CMFs for commonly used safety treatments, but not currently documented within the CMF Clearinghouse, could be developed.


  • English


  • Status: Proposed
  • Funding: $500000
  • Contract Numbers:

    Project 17-123

  • 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:

    Turner, Anne-Marie

  • Start Date: 20230725
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01888639
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 17-123
  • Files: TRB, RIP
  • Created Date: Jul 25 2023 8:17AM