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U.S. Department of Transportation

Federal Highway Administration

400 Seventh St., S.W.
Washington, D.C. 20590

July 16, 2007

In Reply Refer To: HSSD/CC-35H

Mr. Barry D. Stephens
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, CA 95765

Dear Mr. Stephens:

Thank you for your letter of April 2, 2007, requesting the Federal Highway Administration (FHWA) acceptance of a modification to your company’s QuadGuard® system impact attenuator. This modification to the internal energy absorbing element is necessary to accommodate the changes in materials used by vendors of the crushable cartridges. You requested that we find these modifications to Type I cartridges acceptable for use on the National Highway System (NHS) under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”

The FHWA guidance on crash testing of roadside safety hardware is contained in a memorandum dated July 25, 1997, titled “INFORMATION: Identifying Acceptable Highway Safety Features.”

Type I cartridges are used in the front portion of QuadGuard systems. You conducted instrumented pendulum tests of individual existing Type I cartridges to establish accurate force vs deflection curves. Similar tests of the modified Type I cartridges showed the crush profile to be nearly identical to that of the existing cartridge. To confirm that the new cartridges had impact performance similar to the older cartridges you conducted a NCHRP 350, Test 3-30 (820C, 100 kph, 0 degree angle of impact, with four-foot offset.) This test was chosen because the front mounted Type I cartridges most affect the impact performance of the 820C vehicle and thus would be the worst case scenario. The results from the full scale crash test were also acceptable.

Summary of NCHRP Report 350 Test 3-30
820C Test Vehicle:1993 Ford Festiva
Vehicle Mass:812 kg
Impact Speed:98.3 km/hr
Occupant Impact: 11.5 m/s
Ridedown:14.8 g’s

The results of the testing show that the QuadGuard® system performance using the modified Type I cartridges was similar to the original system, and met the FHWA requirements. Therefore, the modified Type I cartridges described above are acceptable for use in QuadGuard® systems on the NHS when proposed by a State or other highway agency.

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

Sincerely yours,

Signature of George E. Rice, Jr.

George (Ed) Rice, Jr.
Acting Director, Office of Safety Design
Office of Safety



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