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                Safety Eligibility Letter CC-65E
  
  **Hardware Type:**
            Barrier Terminals and Crash Cushions
                          **Code:**
            CC-65E
                          **Date:**
            02/13/2009
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            TrafFix Devices, Inc.
                          **Device Description:**
            Scorpion Attenuator Trailer (Modified) TL-3
                          **View PDF:**
            cc65e.pdf (344.95 KB)
    
    Safety Eligibility Letter CC-65E


			
			
			 
			**Download Version**PDF [345 KB]
			
			DOT logoU.S. Department of Transportation**Federal Highway Administration**
			1200 New Jersey Ave. S.E.Washington, D.C. 20590
			February 13, 2009
		  In Reply Refer To: HSSD/CC-65E
			
			Mr. Geoffrey Maus
            	Chief Design Engineer
                TrafFix Devices, Inc.
                160 Avenida La Pata
                San Clemente, California  92673
           	Dear Mr. Maus:
            This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of a roadside safety system for use on the National Highway System (NHS).
            Name of system:
					Scorpion Attenuator Trailer (Modified)Type of system:
					Truck Mounted Attenuator - TrailerTest Level:
					NCHRP Report 350 Test Level 3Testing  conducted by:
					KARCO Engineering, LLCDate of  request:
					December 6, 2008Date of completed package:
					January 21, 2009You 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.”
            **Requirements**Roadside safety systems should meet the guidelines contained  in the NCHRP Report 350. The FHWA  Memorandum “Identifying Acceptable Highway Safety Features” of July 25, 1997,  provides further guidance on crash testing requirements of longitudinal  barriers.
            **Description**The TrafFix Devices Inc. Scorpion Trailer Attenuator is a trailer  based impact attenuator. It is comprised  of four sections, as illustrated in the drawings enclosed for reference: the  steel tongue section, the aluminum strut section, the aluminum cartridge  section, and the axle wheel assembly. The  steel tongue section incorporates a Telescoping Anti-Rotation System (TARS). The modified Scorpion Trailer Attenuator  covered by this acceptance letter has an overall length of 5.323 m (209.6 in.),  an overall width of 2.410 m (94.9 in.), and weighs a total 701.0 kg (1545 lbs).
            **Description of  modifications:**To reduce the weight of the original Scorpion Trailer  Attenuator (FHWA acceptance letter CC-65B, dated  March 16, 2007), material thicknesses were optimized and in applicable  locations, aluminum was used in place of steel.  Changes were limited to three components: the tongue, center connecting  angles, and the rear diaphragm.
            Reduced  Trailer Tongue weight. The tongue  section which incorporates the Telescoping Anti-Rotation System  (TARS) was tested using thinner steel wall tubing and plate. The original heavier 3-53 tongue tested on September  27, 2006, weighed approximately 731 lbs (283 kg). The lighter 3-53 tongue tested on September  26, 2008, weighed 455 lbs (206 kg).
                Reduced connecting center  angle weight. The set of connecting  angles attach the strut and cartridge together. The original 3-53 heavier steel connecting  angles tested on September 27, 2006, weighed  40 lbs (18.14 kg). The lighter 3-53  aluminum connecting angles tested on September  26, 2008, weighed 13 lbs (5.9 kg).
                Reduced rear diaphragm  weight. The rear diaphragm consists  of the attachment elements for the axle  assembly and Impact Absorber Boxes A and B.  The original heavier 3-53 rear diaphragm support tested on September 27,  2006, was a steel weldment and weighed approximately 170 lbs (77 kg). The lighter 3-53 rear diaphragm support  tested on September 26, 2008, is an aluminum weldment and weighs approximately 65 lbs (29 kg).The total weight reduction resulting from the three design  changes is 435 lbs (162 kg).
            **Crash Testing**Test 3-53 was selected as a “worst case scenario” test as a  result of the extreme load and stress conditions that the Trailer Attenuator  components must undergo during the offset angled impact test. Test 3-53 places the modified TARS design in  severe compressive and tensile stress conditions while exerting a large bending  moment on the entire attenuator system about the pintle attachment point.
            In comparison, a Report 350 3-52 test would impart a similar  peak compression load to the favored impact side, but with significantly less  angled shear load on the attenuator. A  Report 350 3-51 test would impart the most total load into the attenuator, but  the load would be distributed over the entire attenuator, reducing the force on  each load path. The Report 3-51 test  would have a minimal lateral load imparted into the attenuator.
            Post crash test analysis showed that each of the modified  elements – tongue, center angles, and rear diaphragm – performed in a  functionally identical manner to their heavier counterparts. The modified components caused no alteration  in safety performance of the trailer attenuator.
            You noted that the TARS tubes did not undergo any buckling  or deformation upon impact into the truck frame plate. The connecting angles and axle diaphragm  contained all of their attached 
              components. In  addition, the test results for Ride-down Acceleration and Occupant Velocity  were well below the maximum allowable values and nearly equal to the original  3-53 tested values.

            **Findings**Therefore, the modified Scorpion Trailer Attenuator 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 the FHWA letters of acceptance:
            This acceptance is limited to the  crashworthiness characteristics of the systems 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 system 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 system being marketed is significantly different from the  version that was crash tested, we reserve the right to modify or revoke our  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  it will meet the crashworthiness requirements of the FHWA and the NCHRP Report  350.
              To prevent misunderstanding by others, this  letter of acceptance is designated as number CC-65E and shall not be reproduced  except in full. This letter and the test  documentation upon which it is based are public information. All such letters and documentation may be  reviewed at our office upon request.
              The Scorpion Attenuators are patented products  and considered proprietary. If  proprietary systems are specified by a highway agency for use on Federal-aid  projects, except exempt, non-NHS projects (a) they must be supplied through  competitive bidding with equally suitable unpatented items; (b) the highway  agency must certify that they are essential for synchronization with the  existing highway facilities or that no equally suitable alternative exists; or  (c) they 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 system for which the applicant is not the  patent holder. The acceptance letter is  limited to the crashworthiness characteristics of the candidate system, 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.Sincerely yours,
						Signature of David A. Nicol
				  David A. Nicol, P.E.Director, Office of Safety DesignOffice of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

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WASHINGTON, DC 20590

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