What is a roundabout? A modern roundabout is a circular intersection with design features that promote safe and efficient traffic flow. Vehicles travel counterclockwise around a raised center island, with entering traffic yielding the right of way to circulating traffic. Slow speeds are maintained as vehicles must negotiate the around the island and the exit curves. The slow speeds aid in smooth movement of vehicles into, around and out of the roundabout, and help promote safety.

Many road authorities United States and Europe have built roundabouts. Approximately 46 have been built in Minnesota with many more planned or under construction. Agencies that have used roundabouts include Minnesota Department of Transportation, Grand Rapids, Monticello, Richfield, Rochester, Minneapolis, and many others.
Roundabout Diagram

Additional Information

For more information on roundabouts, please check the following links.
  • How About A Roundabout? (PDF) - A brochure on roundabouts, how to use them, and why they are used produced by the Minnesota Department of Transportation and the Local Road Research Board.
  • MnDOT Roundabouts - The Minnesota Department of Transportation (MnDOT) webpage dedicated to roundabouts in Minnesota. The webpage details what roundabouts are, why they are used and how to navigate a roundabout.
  • US DOT Roundabout Brochure (PDF) - A Brochure developed by the United States Department of Transportation explaining what roundabouts are, why they are used, and how to navigate them.
  • IIHS Roundabouts - Insurance Institute for Higher Safety webpage with questions and answers about roundabouts. The webpage also has a short video on roundabouts.

Engineering Department Handouts