Know the rules
Trucks and other vehicles over 7.5 metres long that have a DO NOT OVERTAKE TURNING VEHICLE sign on the back are legally allowed to take up more than once lane to turn at corners, intersections and roundabouts. They can even use a right turn only lane to turn left or at a left turn only lane to turn right.
So, whether you’re turning left, right or you’re at a roundabout, don’t drive past or overtake a turning truck unless you’re absolutely sure it’s safe to do so.