The UK should not be allowed design anything to do with traffic control, they don't know what they are doing. See evidence below.
McBryce.
You say that, and yet in reality those mad (we call them magic roundabouts) actually do work rather well, and it always seems to be a quicker navigating your way around them. I think that the first one was an experimental one in Hemel Hempstead and now they are cropping up at lots of roundabouts with 5 or more roads linking to them.
This video actually uses the same roundabout and shows how to use them and why it makes sense.
This video explains why the Americans dislike them and also explains why they are going to have to get used to them because of increased safety and reduced emissions.
So as it turns out we Brits do indeed know a lot about traffic management and most of the world has been busy copying us.
Big roundabouts work well, unless somebody doesn't follow the rules.
If a car is already in the intersection others approaching, or just reaching the roundabout should give way to them.
The problem mainly arises, when two cars approach the intersection, of which one, car (1), would normally enter the roundabout first, & hence have right of way.
If the driver of car(2) speeds up, so as to enter the system, the two vehicles are in danger of collision, so car(1) is forced to stop.
When car (1) attempts to move into the system after car (2) has gone, they are confronted by a convoy consisting of car(3), car(4) out to car(n).
With big systems, this sorts itself out after a while, but sends the driver of car(1) on their way highly stressed.
There has been an explosion of very small roundabouts.
Here, the problem is much worse.
Cars in an incoming road carrying more traffic both speed up, & tailgate each other, forcing their way through the roundabout, whilst the driver who should have had right of way has to stop, & is stuck with a tailback of indignant drivers behind him, who don't realise the situation, until car(1) finally gets a fleeting chance & takes it, when they each take his place in turn.
The mini-roundabout works fine for those drivers who "bull" their way through, but not so well for those on the other road.
Another delight is when authorities insist upon "beautifying" the centre island part, reducing visibility to the point where "you take your life in your hands", when you enter the thing.
You may well have right of way, but if someone entering can't see you,it doesn't help.
I have already mentioned the roundabout with a hill in the middle.