As an American, I can assure you that we have loads of these
> In 2000, the U.S. only had 356 roundabouts. Over the past two decades, that number has grown to over 10,000.
It's great news all over that the number is clearly increasing, but still a very long long way to go until it becomes widespread.
So 59 000 roundabouts for half the population versus 10 000 in the US.
That's a deficit of 90% per capita :-)
For my other Americans, read the Australian's post above. Can get across an entire town without stopping as a reason to remake our towns with roundabouts.
The us does not have loads of them they are few and far between