This article investigated the relationship of crash rates and traffic operational parameters at roundabouts. The article provides insight into roundabout design standards, particularly for the establishment of setting sight distances. The results presented in the article showed that higher speed differences between the entering and approach speeds yielded higher crash rates. Since higher speed differences were generally observed at sites with longer site distances, the article recommended that performance-based design guidelines be developed in order to establish threshold values. In order to construct a more complete crash analysis and to develop crash estimation models that incorporate geometrical and operational analysis of modern roundabouts, a more comprehensive analysis should be conducted on a larger dataset collected from longer time periods at various roundabouts. The article concluded that more studies should be done to assess the feasibility of roundabout construction as compared to the construction of signalized intersections in the United States. (Author/publisher)
Samenvatting