Used to live near a circle that was large enough for a gazebo (bandstand). Drivers never seemed to have much problem, although I think a car ran through it one night. Missed the gazebo.
Now the ones built locally are small, barely room for two cars between the intersecting roads. They also seem to be too close to businesses where vehicles coming out must wait for the cars slowing down to enter the circle.
Figure 8

Be afraid I'd get stuck in it like poor Charlie on the MTA.