Bridge railings, although technically classified as longitudinal barriers, are listed separately here because they have been previously tested under criteria different from roadside barriers and have not generally been accepted for use on the NHS on an individual basis.
Since August 28, 1986, the FHWA has required that bridge railings used on Federal-aid projects meet full-scale crash-test criteria and has provided listings of those railings meeting these requirements. A May 30, 1997 memorandum [PDF, 28 KB] consolidated earlier listings and established tentative equivalency ratings that relate previous testing to NCHRP Report 350 test levels.
Appendix B5 [PDF, 103 KB] is a combined and sorted listing of the bridge railings included as attachments to FHWA's May 30, 1997 memorandum. Appendix B6 [PDF, 121 KB] identifies the crash test reports for each railing that is referenced in Appendix B5. Appendix B7 contains drawings or sketches of the railings included in Appendix B5 well as subsequent acceptances for which separate letters were issued. Each of the latter drawings is linked to the appropriate acceptance letter.
In addition to these group listings, the FHWA now issues separate acceptance letters for each bridge rail that has been tested to NCHRP Report 350 evaluation criteria and submitted for FHWA review. The design for which individual acceptance letters have been written but are not included in any group listings may be found under Longitudinal Barriers as acceptance letters B-45A, B-53, B-55, and B-66. Some of the accepted bridge rail designs are also shown in the 1995 AASHTO-AGC-ARTBA Guide to Standardized Highway Barrier Hardware, under the SB-Series drawings.
To minimize duplicate crash testing, the FHWA may allow the use of bridge rail designs that are similar to a crash tested design based on an analytic comparison using the methodology outlined in Section 13 of the AASHTO LRFD Bridge Specifications. FHWA policy and an example comparison prepared by the Colorado Department of Transportation are contained in a May 16, 2000 memorandum [PDF, 3.64 MB] signed by Mr. Frederick G. Wright, Jr.
Roadside Design: Steel Strong Post W-beam. A guidance memo was issued on May 17, 2010 on the height of guardrail for new installations. Guidance regarding existing guardrail will be developed in the next several months, in consultation with AASHTO’s Technical Committee on Roadside Safety.