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|
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:
- Our acceptance is limited to the crashworthiness characteristics of the devices and does not cover their structural features, nor conformity with the Manual on Uniform Traffic Control Devices.
- Any changes that may adversely influence the crashworthiness of the device will require a new acceptance letter.
- Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the device being marketed is significantly different from the version that was crash tested, it reserves the right to modify or revoke its acceptance.
- You will be expected to supply potential users with sufficient information on design and installation requirements to ensure proper performance.
- You will be expected to certify to potential users that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for acceptance, and that they will meet the crashworthiness requirements of the FHWA and the NCHRP Report 350.
- To prevent misunderstanding by others, this letter of acceptance designated as number CC-35H shall not be reproduced except in full. This letter, and the test documentation upon which this letter is based, is public information. All such letters and documentation may be reviewed at our office upon request.
- The QuadGuard® is a patented device and is considered "proprietary." The use of proprietary devices specified by a highway agency for use on Federal-aid projects must meet one of the following criteria: (a) it must be supplied through competitive bidding with equally suitable unpatented items; (b) the highway agency must certify that it is essential for synchronization with existing highway facilities or that no equally suitable alternative exists; or (c) it must be used for research or for a distinctive type of construction on relatively short sections of road for experimental purposes. Our regulations concerning proprietary products are contained in Title 23, Code of Federal Regulations, Section 635.411.
- This acceptance letter shall not be construed as authorization or consent by the FHWA to use, manufacture, or sell any patented device for which the applicant is not the patent holder. The acceptance letter is limited to the crashworthiness characteristics of the candidate device, and the FHWA is neither prepared nor required to become involved in issues concerning patent law. Patent issues, if any, are to be resolved by the applicant.
George (Ed) Rice, Jr.
Acting Director, Office of Safety Design
Office of Safety
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