Random Friday Fun Facts: The Swindon Magic Roundabout

Recently on a train trip from Gatwick to Cirencester, I passed through Swindon.  Swindon, in general, isn’t a huge tourist attraction.  In fact, Jasper Fford seems to have built a website dedicated to taking the piss out of Swindon as a tourist attraction (pointing out the double helix carpark as a major sight).

One thing Swindon does have, though, is a Magic Roundabout.

swindon

No, it’s not magic in the sense of teleportation.  It doesn’t transport you to Hogwarts.  What it is, is more of a social experiment in how people react to being thrust into a life threatening junction in their cars.  You can get an “I survived the Magic Roundabout” t shirt.  It’s been named one of the worst junctions in Europe.

Built in 1972 through the help of the Road Research Laboratory (who knew there was such a thing?) the Magic Roundabout was a response to an overflow of traffic from five directions that the regular roundabout couldn’t handle.  Even though it was complicated, it moved more cars than a traditional roundabout (6200 cars per hour vs 5100).

The solution was to build two roundabouts in one.  The first, outer one, flowed clockwise, the way their traditional roundabouts would (remembering traffic drives on the left in England).  But then, on the inside, there’s another roundabout going counter clockwise.  It allows cars to take the shortest route to their exit vs having to drive around all the streets they might not want, taking up road space along the way.

It looks scary at first.  In fact, there are youtube videos dedicated to explaining why it works mathematically.  But when you look at it for more than a minute, and imagine the traffic flowing, you can see it.  Imagine you come up from the bottom road, and you want to do a u turn.  You just use the roundabout the way it was meant to be, and you’re done.  But if you want to turn right on a street above you, you first go into the small traditional roundabout, and then merge into the counter-clockwise one and make your way up to the street you want, and then go back into the traditional layout to make your exit onto the street.  If you want to turn left, you go on the small connecting street that runs between each small roundabout, and can easily bypass having to drive past four streets you didn’t want.

It actually makes perfect sense once you think about it.

But just for fun, here are two Finns demonstrating how NOT to drive the Magic Roundabout!