What action should a driver take when approaching a roundabout?

When approaching a roundabout, a driver should yield to traffic already in the roundabout. This is important because vehicles in the roundabout have the right of way, which helps prevent collisions and ensures a smooth flow of traffic. By yielding, the driver ensures that they do not force their vehicle into the pathway of oncoming traffic, allowing for safer entries into the roundabout.

The other actions listed are not advisable. Speeding up and entering immediately can lead to dangerous situations, as the driver may collide with vehicles already navigating through the roundabout. Stopping and waiting for traffic to clear can unnecessarily hinder the flow of vehicles, as the goal is to yield rather than create additional stops. Circling once before deciding to exit is also inefficient; the driver should have a plan prior to entering to ensure they know which exit they will take, thus allowing for a smoother transition into and out of the roundabout.