Ever since learning how to use those I can't tell you the number of times I've been annoyed to be forced to sit at a slow stoplight, no other traffic is sight, just waiting for it to turn green. (The epitome of that situation was played out in the Iranian film "Secret Ballot" -- IMHO quite worth seeing if you can find a video and don't mind reading subtitles.)
"We call them roundabouts here too. As far as impressive goes, the largest I've seen was in my hometown in Michigan. A couple hundred meters diameter (says faulty memory working over 36 years, maybe only a hundred twenty plus). In the UK the smallest I've seen were "normal" three or four way intersections with a small CD-sized disk in the middle and a little (yellow?) arrow around it going clockwise.
Ever since learning how to use those I can't tell you the number of times I've been annoyed to be forced to sit at a slow stoplight, no other traffic is sight, just waiting for it to turn green. (The epitome of that situation was played out in the Iranian film "Secret Ballot" -- IMHO quite worth seeing if you can find a video and don't mind reading subtitles.)"
North Las Vegas used some at intersections close to schools, just to slow down the "criminal element" who sped through the narrower streets in an effort to elude the POlice. Las Vegas only used them in Summerlin, which is "exclusive"..."they" say...
As for reading subtitles, I like to watch the silent movies on TMC when I have insomnia...:)