The more progressive and more well-planned small towns and cities around the US have actually been building out roundabouts for the better part of a decade now. When I go visit my parents in suburban Washington I go through 4 or 5 roundabouts between the highway and their house. Turns out you can get the majority of suburban Americans on board with a roundabout if you just point out that it meants they probably won't have to stop and idle anymore. Also, usually cheaper.