What action should be taken when approaching a roundabout?

When approaching a roundabout, the appropriate action is to yield to traffic already in the roundabout. This is crucial for ensuring smooth traffic flow and safety. Vehicles inside the roundabout have the right of way, which helps to prevent collisions and maintain a steady movement of vehicles. By yielding, you allow those already circulating in the roundabout to continue without interruption, reducing congestion and minimizing the likelihood of accidents.

Entering without slowing down can lead to dangerous situations since you may not have enough time to assess the speed and distance of other vehicles. Stopping completely before entering the roundabout is unnecessary and can disrupt the traffic pattern, potentially causing confusion. Using your horn to alert other drivers is not advisable and could be deemed aggressive or as a distraction, potentially escalating tensions on the road. Thus, yielding to traffic already in the roundabout is the safest and most appropriate action to take.