Conflict-Based Crash Prediction Method for Intersections

As the number and prevalence of intersection types and configurations increase, it has become more challenging for practitioners to quantify the safety effects of constructing these designs. Currently the American Association of State Highway and Transportation Officials (AASHTO) Highway Safety Manual (HSM) provides safety performance functions for a few conventional intersections based on empirical research, but any deviation from the basic assumptions in the HSM requires the application of one or more crash modification factors (CMFs). Although there are a high number of CMFs from various sources, some apply to alternative intersection forms; fewer apply to complex traditional intersections that diverge from the basic intersections in the HSM. Intersection control evaluation policies and efforts typically promote the consideration of alternative intersections not covered in the HSM, which has limited the ability of practitioners to compare the safety performance of these alternative intersections to conventional designs. One element that is common to all at-grade intersections is the conflict point, the location where two or more paths may cross. Previous research has demonstrated relationships between the number of conflict points at an intersection and the number of resulting crashes over a given time period. Similarly, crash severity can be roughly correlated to conflict type, angle, and speed. Alternative intersections have been touted as an improvement in safety over conventional forms due to a reduction in total conflict points, conflict point proximity, and speed. There is a need for a new methodology to assess a variety of intersections' safety performance from the perspective of conflict point type. The objectives of this research are to: (1) develop a quantifiable method to uniformly identify and describe at-grade intersection conflict point types under different contexts; and (2) develop and validate a predictive methodology, using intersection conflict point types to predict multimodal crash frequency and severity, to supplement those in the HSM Part C models.

• Record URL:
  http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=5348

Language

• English

Project

• Status: Active
• Funding: $550000
• Contract Numbers:

  Project 17-119

• 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:

  Zhao, Yi

• Performing Organizations:

  HDR Engineering

  412 E Parkcenter Blvd
  Boise, ID  United States  83706
• Principal Investigators:

  Cook, Dan

• Start Date: 20240701
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: At grade intersections; Crash modification factors; Crash rates; Manuals; Methodology; Predictive models; Traffic conflicts
• Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; Safety and Human Factors;

Filing Info

• Accession Number: 01845585
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 17-119
• Files: TRB, RIP
• Created Date: May 18 2022 9:54AM