That does not exist over here
And I am not sure that it would work quite well, seeing how people drive.
Roundabout are more common in France, but they start to put these in lots of places here in Belgium too, I find these very useful in many cases.
It allows to not slow down the light traffic, unlike what lights do.
And for heavier traffic it often solves the left-turn problems.
I wish that they put one on this crossroad near my work:
http://maps.google.com/maps?f=q&hl=en&geocode=&q=boulevard+de+l'humanite,drogenb- os,belgium&sll=37.0625,-95.677068&sspn=53.741627,97.294922&ie=UTF8&ll=50.792751,4.300997&spn=0.001324,0- .002969&t=h&z=19&iwloc=addr
Left-turn for cars coming from north is problematic, there is often a long line of cars waiting, mostly because of all the cars coming from south which left-turn too, but have priority (and also due to cars coming from east which have priority on both other roads)