In Michigan: Too many crashes in 3-lane roundabout near Brighton trigger changes
https://www.mlive.com/news/ann-arbor/2018/01/11_million_approved_to_limit_c.html
The article appears to imply that the smaller ones are better, so on that note, large intersections between 6 or 8 lane boulevards are right out for conversion.
That's a rotary...they suck.
"Roundabouts" are only one lane wide. We have both in this state. I hate the rotaries.