Here in the UK, we've got lots of roundabouts from tiny mini-roundabouts (some of which have four junctions) that could easily fit almost anywhere, all the way to gigantic multi-roundabout junctions (https://en.wikipedia.org/wiki/Magic_Roundabout_(Swindon) ).
I can't think of a situation where it's more efficient to have four vehicles all stop at a junction (busy four way stop) vs a roundabout which will allow one or two vehicles to join the roundabout without having to stop.
Here in the UK, we've got lots of roundabouts from tiny mini-roundabouts (some of which have four junctions) that could easily fit almost anywhere, all the way to gigantic multi-roundabout junctions (https://en.wikipedia.org/wiki/Magic_Roundabout_(Swindon) ).
I can't think of a situation where it's more efficient to have four vehicles all stop at a junction (busy four way stop) vs a roundabout which will allow one or two vehicles to join the roundabout without having to stop.