[aaronmdjones]

This is why the UK prefers roundabouts where ever possible. They're much more efficient than a light-controlled junction, since anyone can go when ever there is any suitable gap at any entrance.

Not that we don't lose the plot sometimes too... there are plenty of light-controlled roundabouts near me. One has to wonder why.

[SAI_Peregrinus]

Roundabouts are ideal when there's a single lane in each direction. Once you've got two or more lanes the roundabout requires crossing lanes on entry & exit if you're not in the outermost lane. That reduces the chance that there's a suitable gap at the entrance, lowering throughput.

[moltar]

The funniest one I’ve seen was in Lisbon. There’s a roundabout that has a light on the inside. Not to enter the roundabout! But once you are inside one, you must stop at some point.