The case of France is a quite simple. Governement wanted to lessen road related death, so they actually subventionned city and state to build roundabouts.
They are flourishing everywhere, but at this point there is not much need for it anymore. But they keep building them to keep their subventions, it redistribute money to local company (and also keep mayor in their place).
Sometimes you can drive 100Km without encoutering a single crossroad but hundred of useless roundabouts, it actually reduce speed on main road and provide little but no value to actual cross section.
Half* of the UK's roundabouts are in Skelmersdale, and they provide little function because there are so few cars on the road in the area. They probably increase emissions because you've got to drive that much further to get where you want (The largest of these roundabouts is half a mile in circumference) - and with nothing but grass, woodland and strange "art" sculptures in the middle, they're a huge waste of land.
The most curious definition of 'waste of land' I've encountered in a while. Are national parks also a waste? How about wildlife refuges? Oh! Scotland! That may also qualify.
National parks are places of outstanding beauty. I can assure you Skelmersdale is not.
By waste of land, I mean the place was built using several times more land than was needed for the relatively low population, but some clever fool with government money decide they'd build a bunch of small ghettos separated by large roundabouts.
Sounds miserable. I was imagining a bucolic wonderland of natural beauty, with birds nesting and ancient oaks over shady glens.
My local town is in the process of sticking 'roundabouts' everywhere. Mayor visited someplace and liked them; he's pushing them on us now. Sometimes its just a dumb island in the middle of an intersection; you have to crank around it at microscopic speed which benefits no one.
The worst one has two lanes halfway around; one lane the rest of the way. From the south you can take the right lane and exit north without turning (much). But nobody understands the point; everybody stops and creeps around. So they put up a map(!) so you can figure it out. And 13 arrows and warning signs. All in the interest of 'efficiency'
They are flourishing everywhere, but at this point there is not much need for it anymore. But they keep building them to keep their subventions, it redistribute money to local company (and also keep mayor in their place).
Sometimes you can drive 100Km without encoutering a single crossroad but hundred of useless roundabouts, it actually reduce speed on main road and provide little but no value to actual cross section.