Roundabouts are occasionally used in the US, but they are not a panacea. They require much more space than conventional intersections, and can't easily be converted to traffic lights. It's also difficult for visually impaired people to navigate roundabouts, so it can be hard to be ADA-compliant.
The Department of Transportation published a study about 20 years ago about roundabouts [1]; I'm sure most American Civil Engineers doing road design are familiar with it.
[1] https://www.fhwa.dot.gov/publications/research/safety/00068/