Our design team’s goals were to deliver a roundabout design to help address high speeds at the intersection, make accommodations for high truck traffic movements, and minimize impacts to adjacent properties and potential unmarked burial sites while maximizing safety and functionality.
Several layouts were evaluated to improve the overall design of the project and reduce right-of-way impacts, resulting in significant project savings. Despite the complexity of constructing a roundabout while maintaining traffic through an active intersection, the roundabout was selected due to the ability to provide significant safety benefits with minimum disruption to traffic flow.
Speed reductions were achieved using large horizontal curves that eventually decreased in radius, raised curbs, and splitter islands approaching the intersection. The center island landscaping, lighting, and advanced signage alerted drivers to the upcoming roundabout from a distance.
One challenge during the project was the introduction of grave sites within the Florida Department of Transportation (FDOT)’s right-of-way. Cardno’s cultural resources team evaluated the grave site locations, and worked quickly to adjust the design to avoid any schedule impacts.
Another significant element of the project was public outreach and communications. The public outreach program educated the public on the benefits of modern roundabout designs with 3D simulations showing improved traffic flow. In addition, the public interacted at information meetings with a scale model of the roundabout using toy vehicles to experience various traffic movements.
With the reduced speeds of the new roundabout, severity of crashes will drop significantly (by 82% according to the Federal Highway Administration). This intersection also introduced pedestrian and bicyclists features to the road. Along with LED lighting and center island landscaping, this project will significantly improve safety in the area.
The project won an Outstanding Project Award - Roadway Project from the American Council of Engineering Companies of Florida.