Tesla and the Magic Roundabout

By Brian Clegg

No, not the Magic Roundabout that was a teatime treat on TV many years ago. And not Nikola Tesla either. We are taking about the US electric car company and one of the best-known features of my home town Swindon – our Magic Roundabout.

The reason for this post is that Tesla has been doing some testing of fully self-driving cars in the UK, and a test site they have publicised is getting across the Magic Roundabout. We inhabitants of Swindon are rather proud of our ability to fearlessly cross the Magic Roundabout, but it certainly puts an aspect of nervousness into many who encounter it for the first time.

What can be scary about a roundabout? Because it isn’t really that at all – it is five mini-roundabouts joined together by very short sections of roadway.

The diagram alongside shows the layout of the roundabout, and two possible routes for getting from the bottom left road to the right hand one. This is what makes it so much fun. You can go whichever way you like around the whole structure as long as you stick to proper roundabout protocol on the mini-roundabouts. There is never just one way to get from A to B.

However, the diagram also demonstrates that to a logic-following computer, there really is no complexity to navigating the Magic Roundabout. At each point there are clear options – and it doesn’t really matter if you choose a non-optimal route. You will still end up where you want to go.

For me this is a classic example of showing how an autonomous vehicle can cope better with things humans are bad at. We struggle initially with getting our heads around the Magic Roundabout as a single system, rather than simply heading towards where you want to go, considering each mini-roundabout in its own right. But computers have always been better at some things than humans. Just because Excel is a lot better than me at adding up a column of numbers doesn’t mean it can write books better than me.

A real test for a Tesla in fully automated mode, or any other self-driving car, is things that people are good at, but provide a challenge to computers. A far better test as far as UK driving goes, would be navigating the country roads just a couple of miles from the roundabout. These involve tight turns, around which you might meet a sheep or a bicyclist, requirements to give way where visibility is not great, potholes to avoid and potential debris in the road from tree branches to horse muck. (Oh, yes, and knowing how to pass a horse and rider travelling in the opposite direction.) If a Tesla could do all of that, I’d be impressed. But the Magic Roundabout? Pah.

Here’s the Tesla in action – of course it looks impressive, but we are looking at it through human eyes:

Tesla image from Unsplash+ by Tesla Fans Schweiz. Magic roundabout image from Wikipedia by Hk kng, cmglee

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Now Appearing is the blog of science writer Brian Clegg (www.brianclegg.net), author of Inflight Science, Before the Big Bang and The God Effect.