FHWA Resource Center
SAFETY & DESIGN TEAM
Safety and Design Technical Services Team
Caption: Photo of a roundabout intersection with cars driving through it.
PRODUCTS & SERVICES
A roundabout is a one-way, circular intersection in which traffic flows around a center island. Roundabouts are designed to meet the needs of all road users-drivers, pedestrians, pedestrians with disabilities, and bicyclists. A roundabout eliminates some of the conflicting traffic, such as left turns, which cause crashes at traditional intersections. Because roundabout traffic enters or exits only through right turns, the occurrence of severe crashes is substantially reduced. Small-angle collisions that may occur as a result of a right-hand turn are typically less severe than other types of collisions.
One of the reasons that roundabouts succeed is because their design effectively decreases driving speed to typically 48 kilometers (30 miles) per hour or less.
Roundabouts have the following benefits over traditional signalized intersections:
- Crashes are less severe than other intersection crashes.
- Safer than traditional intersections.
- Cost-effective way to improve intersection safety.
- Increased traffic capacity and improved traffic flow.
- No signal equipment to maintain.
- Aesthetic benefits.
The professionals of the Safety & Design team have experience with all aspects of roundabout design and can suggest ways in which they can improve traffic flow safety in a community.
Transportation professionals seeking training in the design of roundabouts, ideas for sharing information with the local community, or assistance with a building project may contact the Resource Center Safety & Design team.
Workshops, Seminars and Courses
Roundabouts - Planning and Designing Safer Intersections
This workshop presents an introduction to planning and designing roundabout intersections for safety. The workshop is highly interactive with numerous discussions, examples, case studies and exercises.
The workshop covers the following topics:
- Distinguishing modern roundabouts from other types of circular intersections.
- Roundabout safety results and predicting intersection safety performance.
- Traffic operational models and capacity calculation exercises.
- Planning considerations for making good intersection design decisions.
- Public education strategies.
- Roundabout geometric design principles.
- Signing and marking.
- Pedestrian and bicyclist accommodations.
- Roundabouts on rural high-speed corridors.
- Single and multi-lane roundabouts.
Caption: Aerial photo of a roundabout.
For more information contact:
Mark Doctor, Safety Engineer
SAFETY AND DESIGN TECHNICAL SERVICES TEAM