[vidarh]

I don't think it's that common - I've only seen it a couple of places, but it happens. Most places in Europe I've been, there's car traffic going in parallel with the pedestrians.

The most "famous" example in Europe of all traffic being stopped at once, I suspect is Oxford Circus in London, where they changed to start doing this a few years ago.

The reason to do it there, though, was to allow pedestrians to walk in any direction (diagonally as well) across one of the busiest crossings in the country. This BBC article refers to it as a "Japanese-styled system":

http://news.bbc.co.uk/1/hi/england/london/7997569.stm

[andrewaylett]

Most sets of traffic lights in the UK allow diagonal crossing, as in all traffic stopped at once, it's just not that common to encourage pedestrians to cross diagonally. What you never get in the UK is the condition described above, where pedestrians and drivers are directed to use the same bit of road.

There are also plenty of junctions where some car drivers are allowed to proceed while on other bits of the road, pedestrians are allowed to cross. So (typically) each road into the junction has a central island and the pedestrian controls for each half of the road are separate. On those junctions, it's never safe to go across the middle as there will always be some traffic moving.

[jgh]

There are a few of those intersections in the US and Canada as well, normally called "scramble" intersections here I think.