Federal Highway Administration
|Subject:||INFORMATION: Generic Cable Barriers (Supplement to Acceptance Letter B-64)||Date: September 12, 2005|
|From:||John R. Baxter, P.E. /Original signed by John R. Baxter/
Acting Associate Administrator for Safety
|In Reply Refer To: HSA-10|
|To:|| Resource Center Managers
Federal Land Highway Division Engineers
Mr. Dwight A. Horne's February 14, 2002, memorandum, "Nonproprietary Guardrails and Median Barriers" (FHWA Acceptance Letter B-64), identified most of the commonly used non-proprietary roadside and median barriers that were considered to have met all NCHRP Report 350 test and evaluation criteria for their indicated test levels. Since its issuance, several inquiries have been made concerning the status of specific cable barrier designs that were not listed in that memorandum. Please be advised that the following roadside cable barrier is considered to be crashworthy at TL-3 and may be used on the NHS:
Weak-Timber Post Cable Guardrail (AASHTO SGRO1c/G1-c)
Note also that the 3-Strand cable median barrier shown in Figure C.1b in the 2002 AASHTO RDG) is classified as an NCHRP Report 350 TL-3 barrier. An earlier cable median barrier design, shown in Table C.1 in the 1996 edition of the RDG, has a greater separation between each cable which raises the top cable height to 33 inches while the bottom cable remains at a nominal 21-inch height. This design may also be considered acceptable as a TL-3 barrier.
All of the above designs must be used with a crashworthy cable barrier terminal when installed on the NHS.
(Original Signed by)
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety
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