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                Safety Eligibility Letter B-141D
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-141D
                          **Date:**
            03/19/2009
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Trinity Industries
                          **Device Description:**
            CASS of 141C on 6:1 slopes or flatter
                          **View PDF:**
            b141d.pdf (1.26 MB)
    
    Safety Eligibility Letter B-141D

			
			 
			**Download Version**PDF [1.29 MB]
			
			DOT logoU.S. Department of Transportation**Federal Highway Administration**
			1200 New Jersey Ave. S.E.Washington, D.C. 20590
			March 19, 2009
			In Reply Refer To: HSSD/B-141D
			
			Mr. Brian Smith
				Trinity Highway Products, LLC 
				P.O. Box 568887
			Dallas, TX 75356-8887
				
			Dear Mr. Smith:
			This letter is in response to your request for the Federal  Highway Administration (FHWA) acceptance of modifications to your CASS cable  barrier roadside safety system for use on the National Highway System (NHS).
			Name of  system:
					Trinity’s CASS 3-Cable  BarrierVariations:
					Test Level 4 on 1:6  slopes or flatter, 3 CablesTest  Level 3 on 1:4 slopes, 4 CablesTest  Level 4 on 1:6 slopes or flatter, 4 CablesType of  system:
					Three or four cable  barrier systemTest  Levels:
					NCHRP Report 350  TL-3 and TL-4Testing  conducted by:
					Texas Transportation InstituteDate of  requests:
					October 20 and  December 11, 2008You requested that we find these systems 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 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 FHWA has accepted the CASS  3-cable system to test level 3 (TL-3) criteria in the following FHWA Acceptance  Letters:
			B-119 (3m / 8 ft post spacing), dated May 13, 2003
				B-119A (5m / 16.5 ft post spacing), dated May 13, 2003
				B-119B (2m / 6.5 ft post spacing), dated August 28, 2003
			The FHWA acceptance letter B-141C  Revised (dated November 14, 2008) found the Trinity CASS 3-cable barrier system  acceptable for use on a 1:4 slope per NCHRP Report 350 TL-3 conditions.  The 19 mm (3/4-inch) diameter standard  cables were set at heights of 445 mm, 745 mm, and 1060 mm (17.5, 29.3,  and 41.7 inches) above the ground surface, measured to the center of each  cable. Tension of the cables was set at  24.9 kN (5600 pounds force) for the tests.
			Your first request is for this  TL-3 barrier to be used as a TL-4 barrier on slopes of *1:6 or flatter*.  This system differs from the previously accepted TL-4 system (see FHWA Acceptance  Letter B-157 dated April 23, 2007)  only in the heights of the cables and how the bottom  cable is attached to the post. As the  proposed spread of the three cables is wider than the previously accepted  system we concur that these changes should have no adverse affect on the  crashworthiness of the barrier system.
			Your second request is to add a  fourth cable (between the top and middle cables) to the TL-3 barrier accepted  in B-141C. Because the addition of the  fourth cable at a height of 949 mm (37.375”) above the ground surface, measured  to the center of the cable is not considered to be detrimental to the  performance of the crash tested system, and is indeed likely to increase the  capacity and improve the performance, the CASS system described in Letter  B-141C with the added cable is acceptable. It is understood that the  added cable will have its own anchorage just like the other cables.
			Your third request is to add a fourth cable (between the  top and middle cables) to the TL-4 barrier on 1:6 or flatter slopes discussed  above. Because the addition of the  fourth cable at a height of 949 mm (37.375”) above the ground surface, measured  to the center of the cable is not considered to be detrimental to the  performance of the crash tested system, and is indeed likely to increase the  capacity and improve the performance, this CASS system with the added cable is  acceptable. It is understood that the added cable will have its own  anchorage just like the other cables.
			Finally  you requested that these CASS Systems be acceptable with post spacings from 2.0  m (6.5  feet) to 5.0 m (16.5 feet) and with the same range of post embedment types  (direct driven, set in driven tube, set in tube sleeve in concrete  foundation). These variations have been  shown to be crashworthy in earlier testing and will be acceptable for these  systems. The end terminal acceptance for  these systems was included in acceptance letter B-157, dated April  23, 2007.
			CASS System Variations
				Date
                FHWA Letter
                CASS System Description
                Cable Heights    inches
                DrawingNovember 17, 2005
                B-141
                3-Cable
                TL-4    on 1V:6H Slopes
                20.9", 30.5",    38.1
                SS-740April 23, 2007
                B-157
                4-Cable
                TL-4 on 1V:6H Slopes
                20.9", 26.2",    30.5", 38.1"
                SS-740-740-4November 14, 2008
                B-141C
                (Revised)
                3-Cable
                TL-3 on 1V:4H Slopes
                17.5", 29.5",    41.7"
                SS-730-4:1-3CThis letter
                B-141D
                3-Cable
                TL-4 on 1V:6H Slopes
                17.5", 29.5",    41.7"
                SS-730-4:1-3CThis letter
                B-141D
                4-Cable
                TL3 on 1V:4H Slopes
                17.5", 29.5",    37.4", 41.7"
                SS-730-4:1-4CTL4 on 1V:6H Slopes**Findings**The 3- and 4-cable barrier systems described above are  acceptable for use on the designated or flatter slopes under NCHRP Report 350  TL-3 or 4 conditions as noted. The  systems are detailed in the enclosed drawings and are acceptable for use on the  NHS when such use is acceptable to 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 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 B-141D 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 CASS barriers 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,
						David A. Nicol
						David A. Nicol, P.E.Director, Office of Safety DesignOffice of Safety U.S. DEPARTMENT OF TRANSPORTATION

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