Roundabouts are normally applied to intersections where there is a large volume of traffic that traffic lights can't handle without backups. The 18 mile and Van Dyke intersection is great example. Michigan seems to use them where appropriate. Spent some time in the UK. On a rural highway in the US, you can time the lights never stop. In the UK, YOU have to stop at EVERY roundabout which is SO annoying! But they work just fine during a war or during a black out.