Evaluation of Concrete Median Barrier Delineation Under Poor Visibility Conditions Final report. 8 Feb 01-7 Dec 02

摘要

In this research, a nationwide survey, durability test, and visibility test were conducted for concrete median barrier delineation. This research was in response to problems PENNDOT was encountering with delineators becoming detached due to harsh conditions in roadside areas, as well as visibility problems in spot locations prone to fog. From the results of the research it was recommended that, in areas prone to poor visibility conditions, PENNDOT consider decreasing the longitudinal spacing and providing delineation lower on the barrier than shown in the standards. It must be noted that due to time restrictions, this research was not able to address whether delineators remain effective when exposed to conditions near the pavement surface over a long period of time. This should be monitored by PENNDOT in the appropriate instances. With respect to durability, in instances where the 'peel-n-stick' delineators are comparable in price to obtaining the delineators and adhesive separately, that special consideration should be given to the 'peel-n-stick' delineators. Their installation time was found to be less, and their durability was perfect over the one-year period monitored. They should also be given special consideration in instances where traveler delay due to the traffic control set up to install the delineators is critical. Finally, the literature review revealed that the ultimate solution to delineation under poor visibility conditions is light-emitting delineation. The Department should remain open to such solutions and make their implementation a long-term objective.