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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter SS-148A

Safety Eligibility Letter SS-148A - Safety

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

August 16, 2011

In Reply Refer To:

Mr. Ryan Beduhn
Swing SAFE Mailbox Supports, LLC
3216 Kentucky Avenue S.
St. Louis Park, MN 55426

Dear Mr. Beduhn:

This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of a modified mailbox support for use on the National Highway System (NHS).

Name of system: SwingSAFE Swing-Away Mailbox Support
Type of system: Mailbox Support
Test Level: NCHRP Report 350 at TL-3
Testing conducted by: not applicable
Date of request: January 28, 2011
Date received by FHWA: February 4, 2011

You requested that we find a modified version of a previously-accepted mailbox support acceptable for use on the NHS under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features."

Roadside safety devices should meet the guidelines contained in NCHRP Report 350 if tested prior to January 1, 2011, and the guidelines in AASHTO's Manual for Assessing Safety Hardware if tested after that date.  The FHWA memorandum "ACTION: Identifying Acceptable Highway Safety Features" of July 24, 1997, provides further guidance on crash testing requirements of longitudinal barriers and crash cushions.  Modifications to previously-accepted devices that are not likely to affect crash performance may be accepted without additional crash testing.

You requested formal FHWA acknowledgement and acceptance of several changes made to a previously-accepted design for a mailbox support.  Your SwingSAFE support is similar to the original Minnesota Department of Transportation (MinnDOT) swing-away mailbox and to a modified version of the original that was tested by the Texas Transportation Institute in 2006. The latter design was accepted for use on the NHS in our letter SS-148 on May 8, 2007.  Based on staff review of the changes detailed below, the FHWA agrees that your modified support remains a crashworthy TL-3 design under NCHRP Report 350 and that no additional testing need be done.

The Minnesota Swing-Away Mailbox Support was originally designed and tested in 1993.  The original design utilized a cantilevered arm that permits snowplow operation beyond the shoulder or curb, thereby reducing both snow drifting on the roadway and the potential for damage to the mailbox support.

The Modified Minnesota Swing-Away Mailbox Support (2006 version) was based on the original design and includes several modifications, the following of which were noteworthy:

Your current request described changes made to the Modified MinnDOT design.  These include the following:

A drawing of the Modified SwingSAFE Swing-Away Mailbox Support is enclosed.

No additional testing was conducted.

Based on the considerations noted above, the FHWA agrees that the SwingSAFE Mailbox Support, as modified, is acceptable as an NCHRP Report 350 TL-3 support.

Please note also that the following provisions apply to FHWA letters of acceptance:


Sincerely yours,

/* Signature of Michael S. Griffith */

Michael S. Griffith
Director, Office of Safety Technologies
Office of Safety


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