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                Safety Eligibility Letter B-25A
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-25A
                          **Date:**
            02/02/2010
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Energy Absorption Systems
                          **Device Description:**
            Barrier Gate median barrier closure TL-4
                          **View PDF:**
            b25a.pdf (311.7 KB)
    
    Safety Eligibility Letter B-25A

						
			DOT logoU.S. Department of Transportation**Federal Highway Administration**
			1200 New Jersey Ave. S.E.Washington, D.C. 20590
			February 2, 2010
			HSSD/B-25A
			
			Mr. Barry  D. Stephens, P.E.
            	Sr. Vice President Engineering
                Energy Absorption Systems, Inc.
                3617 Cincinnati Avenue 
                Rocklin, CA 95765
            Dear  Mr. Stephens :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:
                	BarrierGate at Test Level 4Type of system:
                	Positive  longitudinal barrier/gateTest Level:
                	NCHRP  Report 350 TL-4Testing conducted by:
                	E-Tech Testing Services, Inc. and L.I.E.R. (France)Task Force 13 Designator:
                	SGM20Date of request:
                	June  13, 2008Date of completed package:
                	February 27, 2009Request initially acknowledged:
                	February 3, 2009
            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.”
            **Requirements**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. The FHWA Memorandum  “Identifying Acceptable Highway Safety Features” of July 25, 1997, provides  further guidance on crash testing requirements of longitudinal barriers.
            **Description**The  BarrierGate has been tested and was accepted as a Test Level 3 (TL-3) product via  FHWA letter  B-25 on April 19, 1993. You provided the  following in support of your request that the BarrierGate be considered a TL-4  barrier system:
            Per NCHRP Report 350 page 31, Table 3.6, the impact capacity of a TL-3  barrier with the pickup truck is equal to the impact capacity of a TL-4  barrier:
            	NCHRP 350 Test 3-11 calls for a 2000kg/100kph/25 degree impact into the  side of the barrier. Using the formula to calculate impact severity (I.S.  = 1⁄2 m (V sinθ)2, the impact severity for this test is 138 kJ.  The BarrierGate passed this test.
                	NCHRP 350 Test 4-11 also calls for a 2000kg/100kph/25 degree impact into  the side of the barrier. The impact severity of this impact is 138 kJoules, the same as TL-3.
                    The BarrierGate’s TL-4 capacity with the 2000 kg pickup truck should not  be in question because the unit has  already passed Test 3-11.
           		TL-4 also requires an 8000kg/80kph/15 degree  impact into the side of the barrier (NCHRP Report 350 Test 4-12). The Impact Severity of this test is 132.5 kJ,  which is less than the pickup truck test. The 4-12 test is principally conducted to evaluate vehicle stability and trajectory.  The 8000s box truck has a higher center of gravity than the 2000p pickup so it  has a greater tendency to roll over rigid barriers. The argument supporting Energy’s position  that the BarrierGate will work well during a TL-4 test is tied to the known  impact performance of a very similar Energy product called the Vulcan (*steel*)  Barrier:
                	Like the BarrierGate, the Vulcan was accepted as a TL-3 product in FHWA Acceptance  Letter B-134 on February 14, 2005.
                    	Both the BarrierGate and the Vulcan Barrier have very similar thrie-beam  side profiles with the exception that the Vulcan Barrier is wider at the top  than at the base, and the BarrierGate is narrower at the top than at the base.
                        The BarrierGate profile is 2 inches taller than the Vulcan Barrier (34 inches  for the BarrierGate vs. 32 inches for the Vulcan). This extra 2 inches  will help improve the stability of the high center of gravity 8000s trucks used  in the TL-4 test.
                        Even at the shorter height of 32 inches, the Vulcan Barrier successfully  passed a full-scale city bus test (European test EN-1317 Test H2 = 13,000kg (bus)/70kph/20 degrees) at the LIER facility in France. The impact  severity for this test was 287 kJ, twice the impact severity of a TL-4  test. Like the 8000s vehicle required for the TL-4 test, the city bus  used in this H2 test had a high center of gravity. Very little bus roll,  pitch or yaw was noted during the impact. The bus was very smoothly  redirected. The FHWA accepted the Vulcan  Barrier at TL-4 in Acceptance Letter B-134D dated August 29, 2008.
                 		The positive slope of  the upper portion of the BarrierGate (vs. negative slope of the Vulcan) is not  a concern relative to passing the TL-4 test. This conclusion is reached after considering  that the positive side slope of the BarrierGate is 6 degrees. We know that standard New Jersey wall is smooth,  has the same slope of 6 degrees, and its height is 2 inches shorter (only 32 inches  tall). We also know that the New Jersey wall has  successfully passed NCHRP Report 350 TL-4 testing. The BarrierGate’s thrie-beam side ribs will  help keep the 8000p from climbing the barrier, the shallow 6-degree side slope will induce no greater  upward ramping (vs. the New Jersey  wall), and the extra 2 inches of height will further help stabilize the high  center of gravity 8000s box truck and keep it from climbing over the  BarrierGate.In  summary we concur that the BarrierGate may be classified as a TL-4 barrier  because:
                	a) the  BarrierGate has shown that it can handle138 kJ of impact energy (TL-4  capacity), 
                    b) the  BarrierGate has a similar side profile as the Vulcan which has successfully  redirected a large/high-CG city bus as described above, c) New Jersey concrete  barriers that are shorter and have a greater side slope than the BarrierGate  pass at NCHRP Report 350 under TL-4 conditions and d) because the BarrierGate  is 2 inches taller than the Vulcan.
              	**Findings**The system described above and detailed in the enclosed  drawings is acceptable for use on the NHS under the NCHRP Report 350 TL-4  conditions, 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-25A 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 BarrierGate is a patented product 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  re2/2/search 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 Design
							Office of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

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