[loupgarou21]

I know of four roundabouts in my area (Minnesota.) Two work just fine and are properly marked.

One is completely useless, it's actually a series of 6 roundabouts attempting to control traffic in a shopping complex. The traffic level is so low that it might as well be normal, uncontrolled intersections.

One is used instead of a cloverleaf or stoplights to control the on/off ramps to a freeway. It's terribly marked and there is no way to know what lane you need to be in or where you ultimately need to go unless you've used it before. I have actually seen people get so confused that they just slam on their brakes and stop in the middle of the thing.