Guidelines for Attachments to Bridge Rails and Median Barriers
Eric Keller, Dean Sicking, Ronald Faller, Karla Lechtenberg, John Rohde
Highway agencies are often presented with the need to add attachments of various configurations to the top or backside of crashworthy traffic barriers. Although, the National Cooperative Highway Research Program (NCHRP) Report No. 350 offers guidance for the safety performance evaluation of traffic barriers, it offers no guidance toward the evaluation of attachments on or near these barriers. The objective of the research project was to collect crash test data relating to bridge rails and median barriers, to collect information about common attachments to traffic barriers, and to evaluate this information for the purpose of developing guidelines for the design and placement of traffic barrier attachments. A comprehensive review of full-scale crash testing of bridge rails and median barriers was conducted in order to establish Zones of Intrusion (ZOI's) for traffic barriers. The primary goal of this review was to identify the extent that a pickup or single-unit truck intrudes over the top of a traffic barrier during a vehicular impact. A field site investigation was undertaken to determine the types of devices commonly attached to traffic barriers. The field survey also categorized the traffic barriers which contained attachments. Finally, based on the combined results from the crash test review and the field investigation, recommendations for the placement and design of attachments are made.
Highway Safety, Roadside Appurtenances, Bridge Rail, Median Barrier, Barrier Attachment Guidelines, Zones of Intrusion