Object Markers at Narrow Bridges on Low Volume Rural Highways

摘要

Bridges are a necessary part of any roadway system. Their construction requires a211u001emore sophisticated engineering design analysis and a higher construction cost 211u001ethan that for the roadways connecting them. Until relatively recently, bridge 211u001ewidth on low volume roads was not a major concern and would often be reduced for 211u001eeconomic reasons. This practice has resulted in narrow bridges on many low volume 211u001erural highways. Bridges and culverts that are narrower than the approach roadway 211u001emay cause problems for a driver because they violate his/her expectations. 211u001eTherefore, it is necessary to provide positive guidance so that the driver has 211u001esufficient information to safely negotiate the narrow bridge or culvert. In such 211u001ecases, the Manual on Uniform Traffic Control Devices (MUTCD) states that Type 3 211u001eobject markers shall be used on each approach. However, if narrow brdiges are 211u001eused by low, wide farm equipment (e.g., a harvester with 24 ft to 30 ft cutter 211u001ebar), the object markers are frequently damaged or knocked-down. Some alternate 211u001earrangement is needed so that bridge ends can be marked in accordance with the 211u001eMUTCD and still allow farm equipment to pass over the bridge without destroying 211u001eor damaging the object markers.