Designing the geometry of a roundabout involves choosing between trade-offs of safety and capacity. Roundabouts operate most safely when their geometry forces traffic to enter and circulate at slow speeds. Designing a roundabout is a process of determining the optimal balance between safety provisions, operational performance, and large vehicle accommodation. Many of the design techniques are substantially different for single-lane roundabouts than for roundabouts with multiple entry lanes. The process of designing roundabouts, more so than other forms of intersections, requires a considerable amount of iteration among geometric layout, operational analysis, and safety evaluation.
This course presents guidelines on the design of traffic elements, illumination, and landscaping associated with roundabouts. The design of these elements is critical in achieving the desired operational and safety features of a roundabout, as well as the desired visibility and aesthetics.
Course Objectives:
- Learn about the different types of roundabouts
- Learn elements of geometric design
- Learn general design principles
- Learn to design the traffic elements including signing, pavement markings and work zone traffic control
- Learn about the required illumination
- Learn about landscaping the central island, splitter island and approach
For this course, you will need to study and review Chapter 6 and 7 of the U.S. Department of Transportation & Federal Highway Administration's publication no. FHWA-RD-00-067, "Roundabouts: An Informational Guide" before taking the quiz.
