One of the greatest discoveries made by man is the single-lane roundabout. One of the worst discoveries is the two-lane roundabout.
The center circle requires crossing over traffic twice to get to the exit of your choice creating, in effect, the proverbial accident waiting to happen. Stupid and dangerous.
Single-lane roundabouts, on the other hand, funnel the incoming traffic into one lane, let it revolve until its chosen destination is reached, then let it re-expand shortly after exiting. Smart and safe.
If drivers were smart and courteous enough to use their blinkers to indicate whether they intended to continue around or take the next exit, the world would be a better and happier place, albeit somewhat infinitesimally.