In 1997, the City of Manhattan installed the first modern roundabout in the state of Kansas. Field study of the operation of the roundabout has been conducted by a Kansas State University (KSU) research team. Comparison to comparable traffic flows at stop controlled intersections have been made. Using the measured field conditions as a starting point, the SIDRA computer program was used to evaluate a range of traffic conditions. SIDRA was used to replicate field conditions to test the projected roundabout operation at increasing traffic levels. The results of the roundabout and other types of intersection traffic control were compared using six of the measures of effectiveness available in SIDRA. It was concluded that the roundabout had been a good choice. Several other roundabouts are being constructed or planned in Kansas. The KSU team is also doing "before and after" traffic operations studies at roundabouts in the states of Maryland and Nevada for the Insurance Institute for Highway Safety (IIHS). This paper will present a history of modern roundabout development, a review of the video-camera methodology of data collection being used by the team, present a summary of the presently available study results, conclusions regarding the superior operational effectiveness of roundabout and conclude with a brief summary of the acceptance/non acceptance of roundabouts in Kansas, and conclude with study results indicating that the modern roundabout is significantly safer than other forms of intersection traffic control. (Author/publisher)
Abstract