Effect on Crashes After Construction of Directional Median Crossovers

The purpose was to determine the safety impact of a program to replace bidirectional median crossovers with directional median crossovers on urban arterials. The state of Michigan has adopted this strategy to increase safety and reduce operational problems associated with the lack of storage space in bidirectional median crossovers. Eight arterial road segments were studied, varying in length from 1.17 km to 8.91 km, in which this change had been made. A total of 54 bidirectional median crossovers were replaced on these eight segments. The crash analysis showed an average of over 30 percent reduction in both total crashes and crashes involving at least one injured party. This reduction occurred almost exclusively at the locations in which the bidirectional median crossovers were replaced, with no significant change observed at crossovers that were not changed.