This is an enhanced single-lane design that can be modified to a dual-lane roundabout. To become a dual-lane layout, the splitter islands and the central island are replaced to increase the width for both entering and circulating in the roundabout. The dual-lane configuration was designed first so that all outside curb lines and right-of-way impacts could be established. In addition, all design matrices such as fast path, phi, path overlap, truck movements, and sight triangles needed to be met for both layouts.
The proximity of the WARF building, UW green houses, and a detention basin created considerable site constraints.
Underground utilities were a challenge. A 10-foot box steam tunnel, 50-inch chilled water pipes, electrical tunnels, sanitary sewer, water main, and storm sewers had to be incorporated directly through the roundabout intersection. Utility access points were carefully planned to fit the roundabout design.
The last unique design element was four bus stops. Because this is a heavily traveled bus route, stops were needed on all four exit points. Pull-off lanes for buses were also included in order to eliminate potential congestion at the roundabout intersection.Back to Project Gallery