[tokamak-teapot]

In the UK there are signs at each exit that do their best to ensure you're clear that you're about to take the right one.

When we're not sure that we're about to come off at the right exit, we just go around again. I find myself doing this in unfamiliar places occasionally.

Not sure what your first point is saying, but the fact you can just go around again until you're sure you're going the right way is a great feature, IME.

I think the reason that introducing roundabouts somewhere where people aren't used to dealing with them all the time is ... well, just that. There needs to be enough of them for people to be comfortable with the right way to approach them - and not just them, but others using them, before they work as intended.

In summary: Roundabouts are a really good way of managing a junction, but - like most road features - they need to get to a point of being familiar to most road users before they're as effective as they can be.