Impact Performance Assessment of Barrier Performance at High Speeds

Recent data indicates that sixteen states have speed limits of 75 mph or higher. Seven of these states currently have speed limits of 80 mph, with almost all of them adopting this higher speed within the last 5 years. The AASHTO Manual for Assessing Safety Hardware (MASH) specifies impact speeds for crash testing and evaluation of barrier systems such as guardrails, median barriers, and bridge rails. The highest impact speed defined by MASH for passenger vehicle is 62 mph. This impact speed was derived from analyses of reconstructed crash data that is now nearly 20 years old. Preliminary data from NCHRP Project 17-43, under which a new database of reconstructed run-off-road crashes is being developed, indicates that for highways with a posted speed limit of 70 mph or greater, the 85th percentile impact speed is 77 mph (1). This indicates a need for a higher design impact speed for barriers used on these higher speed roadways. With more states adopting higher speed limits and posting an increasing number of miles of roads with speed limits of 75 mph and higher, there is a growing recognition of the need for evaluating barriers for higher impact speeds in order to maintain the level of safety for motorists on these roadways. There is no determination of recommended design impact speeds for evaluation of barrier systems intended for use on roadways with higher speed limits and no direct assessment of barrier performance at these higher impact speeds through computer simulation or full-scale testing. The objective of this project is to determine impact conditions and barrier designs appropriate for use on roadways with posted speeds of 75 mph and greater. The research will determine appropriate impact conditions for roadways with higher speed limits (75 mph and greater) through crash data analysis; assess performance limits of existing barrier systems using engineering analysis and finite element simulation; and evaluate new or modified barrier systems capable of accommodating recommended design impact conditions using finite element simulation and full-scale vehicle crash testing. The resulting barrier designs will allow updates to appropriate sections of the AASHTO Roadside Design Guide (RDG), and recommended design impact conditions can be incorporated in a future update of the AASHTO Manual for Assessing Safety Hardware (MASH).


  • English


  • Status: Proposed
  • Funding: $600000
  • Contract Numbers:

    Project 22-42

  • 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:

    Bush, Mark

  • Start Date: 20200914
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01707554
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 22-42
  • Files: TRB, RiP
  • Created Date: Jun 3 2019 3:17PM