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Managing Traffic Flow with Roundabouts

The Oregon Department of Transportation, local jurisdictions and consultants continue to look for traffic control methods that provide ways to safely manage the flow of traffic, bicycles and pedestrians through intersections large and small. Roundabouts are one such method.

Guidance for Designers

Roundabout Design Calculator - For each approach, the roundabout calculator produces conflict flow, entry flow, capacity, pedestrian impedance factors, v/c ratio, control delay, level of service and 95th percentile queue.

"Roundabouts: A safer choice" Presentation, 2010

"Modern Roundabouts for Oregon" Research paper, 1998

Resource site, Federal Highway Administration

Guidance for Roundabout Users

Frequently asked questions about driving and cycling through a roundabout

Roundabout Projects

Check out our Flickr album with photos of roundabouts on Oregon highways.

Contact the Roadway Engineering Unit

4040 Fairview Industrial Drive SE, MS 5
Salem, Oregon 97302-1142
Phone: 503-986-3568
Fax: 503-986-3749

Program Contact

Bethany Veil
Senior Urban Design Engineer
Phone: 503-586-8750

Questions about a specific project?

Select the "view details" button from the list below to find a contact for your project of interest.