Alaska Roundabouts
Recreation, Roads and Highways, Interchanges, Roundabouts - Alaska Roundabouts. Shows different facilities, with a focus on Alaska.
http://www.alaskaroundabouts.com/
RoundaboutsUSA
Recreation, Roads and Highways, Interchanges, Roundabouts - RoundaboutsUSA. Written by road engineers.
http://www.roundaboutsusa.com/
Modern Roundabouts - The Web Site
Recreation, Roads and Highways, Interchanges, Roundabouts - Modern Roundabouts. Information including a list of all in the United States and Canada.
https://roundabout.kittelson.com/