Development of a Crashworthy Tangent End Treatment for Low Speed Curbed Roadways

With the increasing interest in multimodal transportation, the demand for appropriate barrier solutions to address roadside safety issues in low-speed urban and suburban conditions has increased. These environments often have closely spaced intersections/driveways, improvements intended to encourage bicycle and pedestrian travel, physical limitations to the available lateral offset, and commonly involve curbed roadways sections. Because of the physical space limitations, barriers have been installed without a crashworthy end treatment (e.g., sloped end treatments on concrete barrier). Systems that have not been evaluated for use in combination with curbs (e.g., crash cushions) and/or those that involve compromises with respect to length of need (i.e., use of gating hardware) have also been installed. Because barriers in these locations are normally installed in combination with curbing, terminals commonly cannot be flared to avoid conflicts with adjacent pedestrian or bicycle accommodations. As a result of these constraints, a viable end treatment for barriers in these environments—whether for new construction or retrofits of existing barriers—should minimize: (1) Length—to allow for installations along roadways with longitudinal constraints (i.e., discontinuities for intersections, driveways, predestination crossings, etc.). (2) Width—to reduce impacts on infrastructure and adjacent pedestrian pathways. (3) Height—to reduce impacts on sight distance and allow for use with low profile barriers, guardrail, and typical concrete barriers/bridge traffic railings shapes. The objective of the research is to develop an AASHTO Manual for Assessing Safety Hardware (MASH) TL-2 Tangent End Treatment that minimizes the required length, width, and height of the system, and can be used in common conditions found in urban and suburban areas—specifically in combination with 6” vertical curb (minimum height)—and that can be transitioned into either TL-2 low profile, TL-3 F-shape concrete, and semi-rigid w-beam barrier systems. The end treatment should be evaluated using a combination of ISPEs, computer simulation, and full-scale crash testing. The final product will be non-proprietary system drawings and specifications that will allow for component manufacturing and installation.


  • English


  • Status: Proposed
  • Funding: $750000
  • Contract Numbers:

    Project 22-52

  • 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:

    Hartell, Ann

  • Start Date: 20220609
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01772929
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 22-52
  • Files: TRB, RIP
  • Created Date: May 24 2021 3:14PM