They're everywhere. Connecting roads large and small, organising and smoothing the conflicting needs of traffic. Helping people get on and off busy motorways, providing a pleasant transition from open road to suburb, making the flow of urban streets more efficient. It's amazing how productive it can be to go in circles.
The humble roundabout has been with us for a century now, in various forms, through all manner of fashions for straight sides and sharp corners, different systems of priority, one way and two way traffic flows.
These days, traffic lights are probably multiplying at a faster rate, and "give way" junctions are far more numerous, but roundabouts are the ones that have suited us best and become part of our culture. To people overseas, they have often become associated with all things British.
So, to mark the centenary, here is a celebration of all things circular - and please, don't forget to indicate.
- Mini-roundabouts and "squareabouts": MT 95/484.
- Signalisation of roundabouts: DSIR 12/181a; DSIR 12/181b.
- Development of roundabout design and policy including "give way to traffic on right" rule: MT 152/55, MT 95/134.
- Columbus Circle, the world's first functioning roundabout by most accounts.
- Letchworth Garden City Heritage Foundation confirm that Sollershott Circus is the UK's first roundabout.
- Alaska Roundabouts is an information site from the Alaska Department of Transportation, with a surprisingly well-researched and written history of roundabouts.