Delineation of Bridges and Culverts in Texas (1366-1F)

This report documents the results of research performed to develop an improved understanding of delineation needs for bridges and culverts (especially those that are "narrow") and how those needs should best be accommodated through the delineation devices currently available for use in Texas. In this project, bridge and culvert delineation needs were approached from a motorist information need/positive guidance perspective. Considering only the driving maneuvers that must be accomplished in order for a motorist to safely negotiate a bridge or culvert, three different bridge/culvert conditions were identified. The type and location of information that motorists need to accommodate each type of maneuver were then examined, and delineation devices available to convey that information were critiqued. A controlled field study designed to investigate whether the amount and type of delineation provided at each of the three bridge/culvert conditions defined earlier affected driver performance found very few significant effects due to delineation. One exception to this finding was that the addition of a painted edgeline taper with transverse markings upstream of the shoulder drop bridge location resulted in subjects exiting from the shoulder 30 to 35 meters further upstream. Although current practices appear adequate at this time, it was recommended that minor adjustments be made to current TxDOT roadway delineation standard sheets to facilitate the understanding and consistent application of these bridge delineation practices statewide.