What should you know about roundabouts?

In a roundabout, the primary rule is that vehicles within the roundabout have the right of way over those trying to enter it. This means that as you approach a roundabout, it is crucial to yield to any traffic that is already circulating. This helps to maintain a smooth flow of traffic and minimizes the risk of accidents. By yielding to vehicles already in the roundabout, drivers can safely and efficiently merge into the flow of traffic, ensuring that the roundabout operates effectively.

The other options do not accurately reflect the proper rules and behaviors related to roundabouts. Stopping before entering a roundabout is not typically required unless there is a stop sign or it is unsafe to proceed. Using your horn is not a standard or necessary practice in this context, as signaling intentions should be done through turn signals rather than honking. Lastly, the rule is that traffic in the roundabout has the right of way, not the other way around, which reinforces why yielding to circulating traffic is crucial for safe driving in these situations.