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                Safety Eligibility Letter B-171
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-171
                          **Date:**
            04/16/2008
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Colorado DOT
                          **Device Description:**
            F-Shaped CMB
                          **View PDF:**
            b171.pdf (1.36 MB)
    
    Safety Eligibility Letter B-171

			 
			**Download Version**PDF [524 KB]
			
			DOT logoU.S. Department of Transportation**Federal Highway Administration**
			1200 New Jersey Ave. S.E.Washington, D.C. 20590
			April 16, 2008
			In Reply Refer To: HSSD/B-171
			
			Tim Aschenbrenner, P.E.
				Project Development Branch Manager
				Colorado Department of Transportation
				4201 East    Arkansas Avenue
				Denver, CO 80222-3400
			
			Dear Mr. Aschenbrenner:
			This letter is in response to your request for Federal  Highway Administration (FHWA) acceptance of a roadside safety system for use on  the National Highway System (NHS).
			Name of  system: Colorado  Portable Concrete Barrier
				Type of  system: Modified F-Shape Concrete Median Barrier
				Test Level:  Test Level 3 (TL-3)
				Testing  conducted by: [N/A; Modification of Oregon CMB in B-86]You requested that we find this system 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, "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 Colorado  portable concrete barrier is a modification of the Oregon barrier covered in FHWA acceptance letter  B-86 dated August 17, 2001. Drawings of  the Colorado barrier, the Oregon barrier, and a comparison of the two  shapes are enclosed for reference. Here  is a brief description of the Colorado  barrier:
			Each 12-foot, 6-inch long barrier  segment is reinforced longitudinally with eight #5 bars. The barrier is 34 inches tall, 23 inches wide  at the base, and 8 inches wide at the top. The distance from the ground to the slope  break point is 11 inches which is 1 inch higher than the standard “F” shape and  2 inches lower than the New Jersey  shape.
			The pin and loop connection consists of  two 3/4-inch A36 steel loops near the top of one segment end, above a single  3/4-inch steel loop near the bottom on the same end. The corresponding loops on the adjacent  barrier segment consisted of a single loop near the top and double loops on the  bottom. When placed together, the single  loops fit between the double loops, forming two connection points, each  consisting of three loops. A one-inch  diameter, 29-inch long ASTM A449 steel pin, with  no nut or retention device, is dropped through the loops to complete the  connection.
			**Crash  Testing** The Oregon barrier was tested by KARCO  Engineering and had a deflection of 30 inches. The modified Colorado barrier is approximately 5 percent  lighter, a factor which should have no significant effect on the  crashworthiness of the barrier system.
			**Findings** We concur that the Colorado  portable concrete barrier system is comparable to the Oregon barrier that was previously accepted  and is acceptable for use on the NHS as a TL-3 barrier when allowed by the  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 system 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-171 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.
				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,
						George E. Rice, Jr.
						*for*
								David A. Nicol, P.E.Director, Office of Safety DesignOffice of SafetyEnclosures U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

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