Guardrail Performance at Various Offsets from Curb for MASH TL-3 Applications

Curbs are used to control drainage, separate pedestrian facilities, limit right-of-way, provide access control, and limit erosion. However, the need for curbs often competes with guardrail installation. For example, a steep slope needs curb to control drainage and erosion, and this steep slope also may need shielding. If a pedestrian facility is near curb, the guardrail will have to be further offset from the face of curb. Typical solutions for curb placed near a guardrail, such as using a sloped curb or reducing curb height, can be difficult to use. Dropping the curb height or sloping a curb may cause Americans with Disabilities Act (ADA) problems (sight impaired pedestrian may unexpectedly enter a roadway). Shorter curbs may not have the hydraulic capacity needed. There have been some crash tests with a curb placed near guardrail. Many of these tests have failed due to guardrail rupture, barrier override, or vehicle instability. Traditionally crash testing has focused on the performance of pickup trucks striking guardrail with a nearby curb. Some recent crash testing has indicated that more research is needed on small vehicles hitting a guardrail near a curb. Crash testing guardrail installed near a curb with pickup trucks has shown the difficulties in using just computer modeling to set beam guard placement recommendations. The objective of this research will be to develop guidelines for the use of the 31-in. MGS adjacent to curbs under Manual for Assessing Safety Hardware (MASH) TL-3 impact conditions. The research will consider the effect of curb geometry, barrier offset from the curb, and barrier height relative to the roadway on the performance of the guardrail. Guidance will be developed for placement of 31-in. guardrail adjacent to curbs based on these parameters. It is anticipated that a combination of previous research, computer simulation modeling, and full-scale crash testing will be required to develop and verify the guidance.


  • English


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

    Project 22-39

  • 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: 20180619
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01672253
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 22-39
  • Files: TRB, RiP
  • Created Date: Jun 18 2018 3:03PM