Guidelines for Implementation of Cable Median Barrier

Abstract

A detailed examination of accidents in Kansas evaluated the need for a cable median barrier. Hard copies of all accident reports from Kansas controlled-access freeways from 2002 to 2006 were reviewed. A total of 525 cross-median events and 115 cross-median crashes were identified. Cross-median encroachment rates were linearly related to traffic volume and cross-median crash rates appeared to have a second-order relationship to volume. Cross-median crashes were much more frequent in winter months and the severity of wintertime crashes was lower. This finding indicates that median barrier warranting criteria may need to be adjusted to accommodate regional climate differences, especially for warranting guidelines based on cross-median crash rates. A relationship was found between cross-median crash rate and traffic volume for Kansas freeways with median widths of 60 ft (18.3 m). This relationship was combined with encroachment rate and lateral extent of encroachment data from the Roadside Safety Analysis Program to develop general guidelines on the use of cable median barriers along Kansas freeways.