One of the most common motorcycle accidents, especially among the non-preventable, in the sense that even a skilled cautious responsible rider is equally as endangered is the failure to yield, car turns left in front of you at a stoplight.
had a friend of ours get really seriously hurt recently, plowed into a car who "failed to yield" on a left turn at a stoplight. turned left in front of the bike. Another friend had a similar accident, hip and back issues for life - car failed to yield, turned left right in front of him. My worst accident, took a helluva chunk outta my leg that were reconstructed with stem cells, and put me on crutches for months - going through a green light and opposing car turned left right in front of me. same thing. none of those would've happened in a roundabout. So that's definitely worth considering. even getting pushed off road by a car traveling aroundabout parallel to you is gonna be much more survivable than plowing into the front corner of a car that's slammed on it's brakes as you roll full speed through a green light.