Cable Median Barrier Guidelines
Dean Sicking, Daniel Albuquerque, Karla Lechtenberg
A detailed examination of accidents in Kansas was undertaken in order to evaluate the need for cable median barrier. Hard copies of all accident reports from Kansas controlled-access freeways from 2002 through 2006 were reviewed. A total of 525 cross-median events and 115 cross-median crashes were identified. Cross-median encroachment rates were found to be linearly related to traffic volume, while crossmedian crash rates appeared to have second-order relationship with volume. Cross median crashes were found to be much more frequent during winter months, and the severity of wintertime crashes was found to be lower. This finding indicates that median barrier guideline criteria may need to be adjusted to accommodate regional climate differences. This is especially true for guidelines based upon cross-median crash rates. A relationship was developed between cross-median crash rate and traffic volume for Kansas freeways with median widths of 60 feet (18.3 meters). This relationship was then combined with encroachment rate and lateral extent of encroachment data from Cooper to develop general guidelines for the use of cable median barriers along Kansas freeways, which typically have 6:1 or flatter slopes.
Highway Safety, Longitudinal Barriers, Cable Guardrail, Roadside Appurtenances, Median Guidelines