They're good in residential areas with smaller streets - one lane in each direction, and cars on the sides of the road. With a 4-way stop sign everything works

They're good in residential areas with smaller streets - one lane in each direction, and cars on the sides of the road. With a 4-way stop sign everything works well, and traffic stays slow since you're not going more than one block without stopping: no room to accelerate to fast speeds. Roundabouts take a lot of space. 2-way stops are dangerous because traffic can be going a bit fast for the small roads, and visibility is low. There's a two way stop near my house and it's always hard to see if another car is coming, until they're almost inside the intersection. Most of the intersections in the area are 4-way and they just work.