Talk:Magic Roundabout (Swindon)

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Why was this constructed? Someone enlighten the readers? —Home Row Keysplurge 08:39, 11 February 2006 (UTC)

• To ease traffic flow, as all 5 roads leading to it are very busy at peak times, and a normal roundabout can't handle the volume. Apparently it works quite well, although I don't know enough about it myself. --Beeurd 02:04, 17 March 2006 (UTC)

Well, that's obvious, but why so complicated and bizarre? Why did they choose a design like this? —Home Row Keysplurge 14:42, 17 March 2006 (UTC)

I think because it allows more traffic onto the road surface at any given moment. If you compare it with the roundabout at the Elephant and Castle in Londonwhich, if memory serves, covers about the same area but only handles traffic from three roads, you can see that the Magic Roundabout utilizes more of the available surface area, and thus (potentially) improves throughput. I don't know if anyone has undertaken a comparative study to see whether the intention was fulfilled :) AncientBrit 22:50, 2 July 2006 (UTC)

In answer to your question why this design was chosen, it wasn't done on a whim; they tried various layouts over several months to determine which was the most efficient. I remember when it was built; the previous roundabout was a conventional design, covering a large area and with a lot of dead space in the middle. It was always busy, and very congested at peak times ( it handles traffic from 5 main roads, plus traffic from industrial sites and the football stadium) The old roundabout was demolished and the area tarmacked, then various designs were laid out with strings of tyres. There was an old bus in the middle which was used as an observation post, and I remember one time they stopped the traffic till queues had built up on all the roads, then let everyone go at once, to test what would happen. (A nostalgic Moonraker, 12 October 2006}

One thing that confuses me about it is that judging by the diagram, it seems that it is possible to take more than one route across the roundabout to get to the road you want to get to. If you are travelling 'straight on' you can either go clockwise or anticlockwise and still travell roughly the same distance. Can anyone confirm this? Joe 1987 01:29, 28 April 2006 (UTC)

Looks that way from the diagram. Assuming there are two possible routes then traffic on each one would be halved, although how much that would be offset by traffic on other routes I couldn't imagine.

On another subject, there needs to be a link to The Magic Roundabout to explain the source of the name.Lee M 13:51, 6 May 2006 (UTC)

To confirm; yes, there are at least 2 routes across from anywhere to anywhere else (Moonraker 12 Oct 2006)

All I know is that I had to use this roundabout once, and now if I have to go through Swindon I find alternative routes. It's just about the scariest experience I've ever faced on the road.(Daz)

I've used it many times. Once you get used to the counterintuitive logic of the possible flows (yes, it is possible to go round counterclockwise) it becomes something of an intellectual challenge to find the quickest (not necessarily shortest) route open to you at the time. It's more motorcycle friendly than car or truck friendly :) AncientBrit 22:33, 2 July 2006 (UTC)

The problem with a normal 5-road roundabout is this: If there's a lot of traffic wanting to go 3 or 4 stops around, that traffic will show up on most of the ring and thus interfere with all the other traffic, whereas traffic going only 1 stop uses only one part of the ring. The MR allows the 'long way' traffic to use a shorter route around, thus less interference. And traffic going CCW around does not interfere with traffic going CW; only when someone wants to get off or on is there an issue. (BTW, I speak not from experience in negotiating roundabouts -- of which I have relatively little -- but in designing and analyzing data packet-switching networks, some of which closely resemble the Magic Roundabout). So yes, of course you can go around either way - that's the point.

It's often said that this is a clockwise roundabout inside five normal roundabouts, but that's stretching the definition of roundabout a long way: on a roundabout you have right-of way once you are in the ring, whereas if you are travelling CW around the MR, you need to yield at each mini-roundabout as you go around. This thing really is 5 separate 3-road roundabouts joined by 5 normal two-way roads (as shown on the sign), albeit these roads are reduced to a very short length.