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                Safety Eligibility Letter CC-101
  
  **Hardware Type:**
            Barrier Terminals and Crash Cushions
                          **Code:**
            CC-101
                          **Date:**
            06/03/2008
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Texas Transportation Institute
                          **Device Description:**
            27-inch high Steel Post Slotted Rail Terminal (SRT-27SP)
                          **View PDF:**
            cc101.pdf (928.55 KB)
    
    Safety Eligibility Letter CC-101



			
		
		**Download Version**PDF [388 KB]
        
        DOT logoU.S. Department of Transportation**Federal Highway Administration**
        1200 New Jersey Ave. S.E.Washington, D.C. 20590
		June 3, 2008
		In Reply Refer To: HSSD/CC-101
        
	    Hayes E. Ross, Jr., P.E., Ph.D.
        	Professor Emeritus
            Civil Engineering Department
            Texas Transportation Institute
            3135 TAMU
            College Station, TX 77843-3135
      	Dear  Dr. Ross:
        This letter is in response to your request for Federal  Highway Administration (FHWA) acceptance of a roadside safety device for use on  the National Highway System (NHS).
        Name of  device: 27-inch high Steel Post Slotted Rail Terminal (SRT-27SP)
        	Type of  device: W-Beam Guardrail Terminal
            Test Level:  TL-3
            Testing  conducted by: Texas Transportation Institute
            Date of  request: November 29, 2007
            Date of  follow-up: March 26, 2008
        You requested that we find this device acceptable for use on  the NHS under the provisions of 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 the NCHRP Report 350,  "Recommended Procedures for the Safety Performance Evaluation of Highway  Features". FHWA memorandum “Action: Identifying Acceptable Highway  Safety Features” of July 25, 1997 provides further guidance on crash testing  requirements of longitudinal barriers.
        **Description**The  Slotted Rail Terminal was first covered by FHWA Acceptance Letter CC-31 dated  December 4, 1999 and followed by CC-31A, CC-51, and CC-51A. Variations include  the original wood post design at 27 inches, a design substituting two steel  Hinged Breakaway Posts for two of the system’s wood posts, and an all-steel  design without blockouts but with the rail mounted at 31 inches. Your present  request is for an all-steel post version with the rail mounted at 27 inches.
      	The  SRT-27SP is:
        An all steel terminal (except for the offset blocks).
        	Standard 6x8 inch routed wood terminal blockout or other FHWA-Accepted  alternative blockouts used at posts 3 through 6.
            Steel Yielding Terminal Posts (SYTP) are used at posts 2 through 6.
            A steel Cable Release Post is used at post 1.
            The rail is detached from the support posts 2 through 5.
            A shelf angle at post 2 provides rail support.
            The terminal is 37.5 feet long with a straight flare and a 4 foot end offset.**Crash Testing**No  additional testing was conducted on the SRT-27SP. Rather you provided a  detailed comparison of test results from tests on earlier versions of the SRT  and evaluated the need to conduct a similar test on the SRT-27SP. The following  barrier terminal tests were reviewed:
        Test  3-30 was conducted on 27-inch and 31-inch tall versions. These were judged  equivalent or more critical than a test on the SRT-27SP.
        	Test  3-31 was conducted on a 27 inch high version which is the critical test for the  pickup truck, and was judged more critical than the same test on the SRT-27SP.
            Test  3-32 is optional for gating terminals.
            Test  3-34. Test 3-31 was conducted on the T-31 guardrail system and proved the  performance of the steel yielding posts.
            Test  3-35 was conducted on a 27-inch high SRT system that was judged to be more  discerning than a similar test on a SRT-27SP.
            Test  3-39 was conducted on a 27 inch high SRT but is a non-discerning test and not  deemed necessary.On  March 26, 2008, you spoke with Mr. Nicholas Artimovich of my staff and  explained the rationale behind each required test and the prior testing that  satisfies NCHRP Report 350 requirements.
     	**Findings** We  concur with your analysis of prior testing and agree that additional tests are  not necessary to qualify the SRT-27SP. Therefore the subject w-beam guardrail  terminal is acceptable for use on the National Highway System when permitted by  a highway agency.
       	Please  note the following standard provisions that apply to FHWA letters of  acceptance:
        This  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, 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-101 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.
            Slotted  Rail Terminals are patented products and considered proprietary. If proprietary devices are specified by a  highway agency for use on Federal-aid projects, except exempt, 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 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  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.Sincerely yours,
                    	David A. Nicol, P.E.
                        	Director, Office of Safety Design
                            Office of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

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