The National Academies

NCHRP 22-40 [Active]

Update to AASHTO M 180-18 and Associated Highway Guardrail Specifications

  Project Data
Funds: $300,000
Staff Responsibility: Christopher McKenney
Research Agency: RoadSafe, LLC
Principal Investigator: Chuck Plaxico
Effective Date: 7/1/2019
Completion Date: 7/1/2021


Many states use AASHTO and ASTM standard specifications for their guardrail components. Changes to the state of practice and to guardrail materials have created a need to revise AASHTO Standard Specification M 180-18, Corrugated Sheet Steel Beams for Highway Guardrail, and its associated material standards, including those referenced in M 180-18.

A lack of consistent standards can increase fabrication costs for hardware suppliers and ultimately transportation agencies. A manufacturer can spend a significant amount of resources matching one state’s standards only to start completely over to match another state’s standards. Consistency of specifications will also help to increase competition, allowing for the possibility of lower hardware costs for transportation agencies.

Recent years have seen an increased focus on the performance of roadside hardware. Research is needed to assure that transportation agencies are specifying and using correct materials in their highway guardrail systems.


The objectives of this research are to (a) perform a comprehensive review of AASHTO M 180-18 and its associated AASHTO and ASTM standards and (b) propose needed revisions to bring the specifications into conformance with current requirements and the state of practice for highway guardrail systems.

The revised standard shall specify—or make reference to standards for—materials for components of the highway guardrail system, including beams, posts, end terminals, connecting hardware, etc.

The proposed revisions and supporting commentary shall be provided to Technical Subcommittee 4d of the AASHTO Committee on Materials and Pavements (COMP TS 4d) and the AASHTO Technical Committee for Roadside Safety (TCRS) for review and possible adoption.


  Work will begin on 7/1/2019.

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