Roundabouts suck, IMHO, and use up way to much space for the benefit. Only thing worse is this diverging diamond intersection they are putting in at 192nd and Dodge where you cross over into the left lane through the intersection and then back over to the right lane. I have yet to see where that saves anyone any time. In about ten years they will be tearing those back out, going "yeah, worked great in all of our simulations, but didn't work out so well in real life". At least that's my opinion having driven through those in Springfield, MO many times.