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Safety Eligibility Letter CC-65F

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U.S. Department of Transportation
Federal Highway Administration

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

April 20, 2011

In Reply Refer To: HSST/CC-65F

Mr. Felipe Almanza
TrafFix Devices Inc.
160 Avenida La Pata
San Clemente, CA 92673

Dear Mr. Almanza:

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

Name of device: Scorpion Truck Mounted Attenuator on lightweight shadow vehicle
Type of device: Truck Mounted Attenuator
Test Level: NCHRP Report 350 Test Level 2
Testing conducted by: Karco Engineering
Date of request: November 29, 2010
Complete package Rec’d: December 1, 2010
Request acknowledged: December 12, 2010

You requested that we find this system 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 the NCHRP Report 350 or the American Association of State Highway and Transportation Officials’ Manual for Assessing Safety Hardware (MASH). The FHWA memorandum “Identifying Acceptable Highway Safety Features” of July 25, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

The following device is found acceptable:

The TrafFix Devices, Inc. Scorpion TMA is a crash cushion which mounts directly to a host vehicle’s rigid frame. It is comprised of three sections: (1) steel mounting section; (2) steel back-up section; and (3) aluminum cartridge section.

The steel mounting section provides a rigid attachment for the interface between the TMA and the host vehicle. The steel back-up section provides a structural mounting frame for the pivot location for the TMA to rotate to the vertical stored position when needed for transport. The aluminum cartridge section is comprised of structural energy absorbing curved aluminum tube framework, and three aluminum crush modules. The device has an overall length of 2.885 m (113.6 in) and overall width of 2.406 m (94.7 in). Enclosures 1 through 3 show the above components.

Crash Testing
The Scorpion TMA was crash tested by KARCO Engineering according to NCHRP 350 test designation 2-51 guidelines. Occupant impact velocities and occupant risk values were within allowable limits in this test. The test vehicle was not penetrated during the test. Enclosure 4 summarizes the results of test 2-51. In this test a 4497 kg (9914 lb) medium duty truck. It should be noted that the support vehicle roll-ahead distance in test 2-51 was measured 4121 mm (162 in, or 13-1/2 ft). Enclosure 5 illustrates movement of the support truck and deformation of the test article.

The Scorpion TMA described above was previously crash tested and accepted by FHWA for use on the NHS in acceptance letter CC-65 dated on July 14, 2000. In test 2-51 a 9000 kg (19,842 lb) dump truck was used. For this current request letter, a smaller truck (4497 kg) was used for test 2-51. Results of the testing indicate that satisfactory results were obtained.

I concur with your request that the Scorpion TMA can be installed on vehicles weighing a minimum of 4500 kg (9920 lb). One element that highway agencies should be aware of when considering use of this product is the roll-ahead distance of 13-1/2 ft that was observed in the crash test.

Therefore, the device described above and detailed in the enclosed drawings is acceptable for use on the NHS under the range of conditions tested, when such use is acceptable to a highway agency.

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


Sincerely yours,

/* Signature of Michael S. Griffith */
Michael S. Griffith
Director, Office of Safety Technologies
Office of Safety


Page last modified on January 17, 2013.
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