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Roundabouts in the USA

See the Kansas presentations

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I travelled to America in 1999 to deliver three major seminars, and 2008 and 2011 to participate in the international roundabout conferences where I delivered workshops and presented various papers.

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.

View of roundabout - near University, Baltimore, MD USA
Two views are shown here of the roundabout near the University; UK designers note the large truck apron and outward drainage. Note also that the blue "go right" arrow is relatively more conspicuous than the ONE WAY sign, which in my opinion is not appropriate. The sign depicting "pass right of the nose" seems unusual to us but an illuminated bollard has now been developed incorporating this symbol.

 Dimondale village (Michigan) has the first proper US mini-roundabout - others have been installed now.

Western world's first mini-roundabout at Dimondale Michigan

Dimondale mini-roundabout - the first in the western hemisphere!
They chose, at great expense, to use UK bollards!
But note the interesting kerbs - we should do this more in the UK.
America are considering the use of UK style bollards with their own symbol in.

Brief Summary

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.

There should be no upper limit to the diameter of a mini-roundabout central island.

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.


TRB Roundabout Taskforce

Links to news articles following 3rd International Conference on roundabouts
at Carmel, Indiana May 18-20:

Links to other pages:

Clive Sawers - December 2014
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