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The Americans have moved along a lot in that time but because of other forms of circular intersection that do not work well such as large rotaries, about the size of our typical motorway intersection roundabouts, there has been much prejudice that has slowed progress. What I really like about their modern roundabouts is their style and landscaping. The use of white concrete really highlights the layouts well as illustrated in the images below.
Dimondale village (Michigan) has the first proper US mini-roundabout - others have been installed now.
Dimondale mini-roundabout - the
first in the western hemisphere!
My special thanks to Tony Redington (Vermont) , Ed Waddell (formerly Michigan) and Tom Hicks (Maryland) for arranging and coordinating the event. As always I seem to learn more from delivering my seminars because of the wide range of experience that others bring. In particular the careful design and size of the truck aprons has clarified a serious issue of design in the UK for mini-roundabouts at crossroads and that is the inadequate size of our current mini-roundabout central islands. At 4m these are rarely sufficient to give anything like adequate deflection for crossing streams.
Also, at the sites I saw, the Americans are not making the mistakes we have made (and continue to make) over crossfalls on the circulatory roadway - their roundabouts are not sunk partly out of sight as we do in the UK - this is pleasing. There is a need for some standardisation on signing and lining (no standard yield line yet).
America has a vast backlog of "unbuilt" potential modern roundabouts; Ed reckons about 25,000 would just about catch up with (western) Europe. There are huge casualty savings possible and I look forward to further visits to the USA if this would be helpful in accelerating the roundabouts' installation process and help to clear the fog of scepticism and mistrust.
That further visit came in May 2008, after a number of visits by our American friends to the UK to try to catch up on where we were. This was the national roundabout conference sponsored by the Transport Research Board. It was preceded by a roundabout workshop sponsored by Ourston Roundabout Engineering.
to news articles following 3rd International
Conference on roundabouts
Links to other pages:
Clive Sawers - March 2012