Eliza - Yes the US abomination commonly called a "traffic circle" is the same sort of thing others call a "roundabout." The roundabout term is heard occasionally in New England where they've been around for a long time, but "traffic circle" is the more common term where they've only recently begun to appear.

I lived for a while in Boston (actually Dorchester) Mass near a classic one called Kosciuszko Circle. This was a small circle where FIVE streets came together. There was a nice little monument in the middle (vaguely resembling a 12 ft tall phallus) with an appropriate sign, another sign on a concrete marker, and a street sign on each of the five streets declaring it to be Kosz*****/Cos***/Koz (whatever) Circle, with a total of SEVEN different spellings of the poor guy's name.

A more representative "modern" circle appears a few miles East of our present location, where a four lane highway with 70 mph (110 kph) speed limit crosses a two lane road with 65 mph (104 kph) speed limit. They couldn't decide which one to put a stop sign on, so they made a circle, with 20 mph (32 kph) speed limit in the circle where the two come together. Since this is out in open country (about 20 miles from the nearest "town") there are no lights, and on a dark night the "signage" gives one about 150 ft of warning that you're coming up on "something." There are lots of skid marks on the pavement from people trying to slow down in time, but for large trucks even the 20 mph "limit" in the circle is a little too fast. (It's a small circle.) Three of the seven times I've gone through that circle, there was a semi or a semi trailer in the ditch, that went off the circle sideways. (The circle is slightly elevated, so that those who tip over can roll down the hill clear of the next crash, which I suppose the "designers" claim was an intentional "safety feature.")

John