KEEPING TRAFFIC ON THE RIGHT SIDE OF THE ROAD

Cross-median crashes pose a significant hazard for motorists across the country, claiming numerous lives and causing millions of dollars of damage each year. This article reports on a program implemented by the North Carolina Department of Transportation (NCDOT) to address this hazard. The author first explores the problem of cross-median crashes, noting that they can take place on both horizontally and vertically curved sections of highways, as well as along straight and flat sections, and the events that lead to a cross-median crash include everything from fatigue and improper lane changes to inattention and medical emergencies. In North Carolina, many freeways were constructed with medians between 11 and 15 meters (36 and 50 feet) due to right-of-way costs and environmental constraints. This compounds the problem because even when vehicles are traveling at appropriate posted speeds it requires only a brief break in one's attention span to cross the median and strike oncoming traffic head-on. The author then describes the research studies conducted to analyze this problem and come up with solutions. The author discusses the three part approach that resulted. The first phase was to install protective median barriers on freeways with cross-median crash histories. The second phase was to systematically protect all freeway sections with median widths of 21 meters (70 feet) or less. The third phase consisted of revising policies to prevent the construction of additional freeway sections with unprotected narrow medians. The author concludes that median barriers have achieved their objective of reducing cross-median crashes and saving lives. One sidebar describes the use of cable barriers.