Roundabouts are designed to accommodate all vehicles, including emergency vehicles, buses, and semi-trucks with trailers. Oversized vehicles and vehicles with trailers may straddle both lanes while driving through a multi-lane roundabout. The edge of the center island is in fact a truck apron that acts as an extra lane for large vehicles and vehicles with trailers. The back wheels of the large vehicle are supposed to ride up onto the truck apron. Because large vehicles may need extra room to complete their turn in a roundabout, drivers should remember to never drive next to a large vehicle in a roundabout.
Watch the Minnesota Department of Transportation video below to see how oversized vehicles navigate a roundabout: