April 8, 2019

An open letter to all in the highway safety hardware and roadside design community.

The Federal Highway Administration (FHWA) is continuing to update our process for issuing Federal-aid eligibility letters for roadside safety hardware systems. Our letters are provided as a service to the States and are not a requirement for roadside safety hardware to be eligible for Federal-aid reimbursement. This letter serves to notify you that FHWA is providing a policy clarification.

FHWA will consider applications for Federal-aid eligibility letters for roadside hardware where design revisions were made during the testing process if such revisions are fully documented in accordance with American Association of State Highway Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH). During crash testing of a device, the manufacturer may decide to make design revisions to improve it. Reference to revisions is in AASHTO MASH 2016 (Section 6.1.2 'Report Contents', pg. 112), and states the following:

'As appropriate, any revisions to the design made during the course of the test program should be fully documented. The documentation should include a detailed description of the revisions and which tests are conducted with the revised design'.

To reemphasize an existing requirement in AASHTO MASH, all test reports that accompany an eligibility letter submission must include a separate section regarding design revisions made during testing of new roadside safety hardware. If no revisions were made during testing, this section should clearly indicate that fact. If design revisions were made, the crash test laboratory should document the following:

• Revision details (i.e.; full description, drawings, and other details) to explain the type and extent of the revision(s).
• Engineering rationale with adequate detail provided to explain the purpose of the revision(s). In other words, it must be clearly stated why the revisions were made to the device during crash testing.
• Engineering assessment of the expected performance on crash tests conducted on the device where design revisions were not present at the time of those tests. Additionally, we may request a detailed engineering analysis.

This requirement enhances the quality of the information available to FHWA when we are evaluating a request for an eligibility letter and increases transparency.

Please contact William P. Longstreet, FHWA Office of Safety, with questions or comments at (202) 366-0087 or will.longstreet@dot.gov

Sincerely yours,

Elizabeth Alicandri
Associate Administrator for Safety