Design and Safety Considerations of Center Line Barriers

Opposite-direction crashes, which involve a vehicle crossing into opposing lanes and impacting other vehicle(s) head on or in a sideswipe collision, account for more than 5,000 fatalities in the United States each year. These collisions most often occur on two-way, two-lane, high-speed rural roads, where opposing traffic is separated only by a center line pavement marking, sometimes supplemented with rumble strips. This type of roadway comprises approximately 69 percent of the national road network, totaling approximately 1.97 million miles. NCHRP Research Report 995: Guidelines for Treatments to Mitigate Opposite Direction Crashes outlines several strategies for reducing opposite-direction collisions. Among them are center line buffer areas, which provide additional space between opposing traffic on undivided roads, and cable median barriers installed within the median of divided highways. For highways that do not have a median, a combined approach of installing barrier within a center line buffer area (hereafter referred to as center line barriers) may be effective. Only a limited number of existing sites in the United States have used this approach, and although these installations may not provide the full barrier deflection distance, a 2016 report titled Performance Evaluation of a Cable Median Barrier System on an Oregon Highway with a Narrow Median by Burns and Bell found this treatment effective in reducing opposite-direction crashes. Research is needed to evaluate the effects of center line barriers on roadway safety, operations, and maintenance. Additional study is also needed to investigate noteworthy practices and design considerations for implementing this treatment effectively. The objective of this research is to identify risk factors for opposite-direction crashes and investigate the safety, operational, and maintenance effects of center line barriers on previously undivided roadways. The research results will be used to prepare a guide with noteworthy practices, including safety performance and design considerations.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=5874
• Supplemental Notes:
  • Contract to a Performing Organization has not yet been awarded.

Language

• English

Project

• Status: Proposed
• Funding: $400,000.00
• Contract Numbers:

  Project 17-141

• 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: 20251222
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Center lines; Crash modification factors; Crash rates; Highway design; Highway safety; Traffic barriers; Two lane highways; Wrong way driving
• Subject Areas: Design; Highways; Safety and Human Factors;

Filing Info

• Accession Number: 01956838
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 17-141
• Files: TRB, RIP
• Created Date: May 29 2025 1:19PM