Edinburgh uses them quite a bit. The problem is that these mean a different way of traffic flow. Usually, you do asynchronous switching, meaning all in one dire

Edinburgh uses them quite a bit. The problem is that these mean a different way of traffic flow. Usually, you do asynchronous switching, meaning all in one direction, then all in the other etc. Here however, you have to switch differently. All directions pedestrians → Car direction 1 → Car direction 2 (or have loads of cars that want to turn block each other in the middle of a junction.)