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                Safety Eligibility Letter CC-103A
  
  **Hardware Type:**
            Barrier Terminals and Crash Cushions
                          **Code:**
            CC-103A
                          **Date:**
            08/22/2011
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Barrier Systems
                          **Device Description:**
            TL-3 U-Mad TMA with Sign Board
                          **View PDF:**
            cc103a.pdf (135.09 KB)
    
    Safety Eligibility Letter CC-103a


			**Download Version**PDF [135.09 KB]

			

			DOT logoU.S. Department of Transportation**Federal Highway Administration**

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

			August 16, 2011

			In Reply Refer To: HSSD/CC-103A

			

	  Mr.  Gerrit A. Dyke, P.E.
	    Vice  President of Engineering and R & D
	    Barrier  Systems, Inc.
	    3333  Vaca Valley Parkway, Suite 800
	    Vacaville,  CA 95688
Dear Mr. Dyke:

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

		  Name of system:

					U-MAD Trailer-Mounted TMAType of system:

					Trailer-Mounted AttenuatorTest Level:

					NCHRP Report 350 TL-3Testing  conducted by:

					not applicableDate of  request:

					December 30, 2010Date received by FHWA

					January 7, 2011You  requested that we find a modified version of your previously-accepted U-MAD trailer  attenuator 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 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.
**Decision:**
  The U-MAD trailer-mounted TMA was  previously accepted as a TL-2/TL-3 design in FHWA acceptance letter CC-103.  This design was modified by the addition of  mounting brackets and a removable sign board assembly, as described below.  Based on the results of your analysis, as summarized  below, the FHWA agrees that your modified trailer-mounted attenuator remains a  crashworthy design under NCHRP Report 350 at TL-2 and TL-3, depending on which  energy-absorbing cartridge is mounted on the trailer.
TL-2 SLED — Sentry Longitudinal Energy Dissipater**Description**
            The basic U-MAD trailer-mounted  attenuator described in detail in FHWA acceptance letter CC-103 was modified to  add mounting brackets for a removable illuminated sign board assembly.  Modifications to the trailer frame consist of two upright steel tubes and  gussets welded to the trailer frame.  The  uprights are 3.5-inch × 2.5-inch × 3/16-inch (90-millimeter × 65-millimeter ×  5-millimeter) steel tubes and the gussets are 1.5-inch × 1.5-inch × 3/16-inch  (40-millimeter × 40-millimeter × 5-millimeter) steel angles.  The sign support frame is made from 2-inch ×  3-inch × 3/16-inch (50-millimeter × 75-millimeter × 5-millimeter) steel  structural tubing designed to accommodate a 4-foot × 8-foot (1.2-meter ×  2.4-meter) sign board.  Enclosure 1 shows  the modified trailer and Enclosure 2 shows the trailer with a TL-3 U-MAD  cartridge and a sign board in place.
            .**Testing**
            The  design of the U-MAD trailer-mounted attenuator is such that an impacting  vehicle is not likely to contact the trailer assembly when it is loaded with a  TL-2 or a TL-3 U-MAD cartridge. The weight of the sign board and mounting  hardware increases the total weight of the unit by appro×imately 12  percent.  Your conservation of momentum  analysis concluded that this minor increase in weight would not cause a  significant increase in the occupant impact velocity reported in test 3-51 for  the un-modified design.  Your structural  analysis further concluded that the sign board mounting structure and hardware  is sufficient to withstand the ma×imum loads associated with an NCHRP Report  350 TL-3 impact.  We have reviewed your  analysis and agree with your conclusions.
**Findings**
  Based on the considerations noted above, the FHWA agrees  that the U-MAD trailer-mounted attenuator, as modified, remains acceptable as  an NCHRP Report 350 TL-2 or TL-3 attenuator. 
Please  note also that the following provisions apply to FHWA letters of acceptance:
This acceptance letter provides an AASHTO/ARTBA/AGC Task Force 13  designator that should be used to identify any new or updated Task Force 13  drawings for this product.
  This acceptance is limited to the crashworthiness characteristics  of the device and does not cover its structural features, nor conformity with  the Manual on Uniform Traffic Control Devices.
  Any design 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, the 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 e×pected to supply potential users with sufficient  information on design and installation requirements to ensure proper  performance.
  You will be e×pected 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 NCHRP Report 350.
  To prevent misunderstanding by others, this letter of acceptance,  designated as number CC-103A shall not be reproduced e×cept in full.  This letter, and 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 modified U-MAD trailer-mounted attenuator is  a patented product and is considered proprietary.  If proprietary devices are specified by a  highway agency for use on Federal-aid projects, e×cept e×empt, non-NHS projects,  they: (a) 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 e×isting highway facilities or that no equally  suitable alternative e×ists; or (c) they must be used for research or for a  distinctive type of construction on relatively short sections of road for  e×perimental purposes.  Our regulations  concerning proprietary products are contained in Title 23, Code of Federal  Regulations, Section 635.411.Sincerely yours,

						*/* Signature of Michael S. Griffith */*

                        Michael S. GriffithDirector, Office of Safety TechnologiesOffice of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

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