What must drivers do when entering a roundabout?

When entering a roundabout, drivers are required to yield to traffic that is already circulating within the roundabout. This rule is crucial for maintaining the flow of traffic and ensuring safety for all road users. Yielding allows vehicles already in the roundabout to continue moving without having to stop or slow down significantly, which helps prevent collisions and promotes efficient traffic flow.

The design of roundabouts aims to reduce the likelihood of serious accidents by minimizing conflict points and allowing for lower speeds at intersections. When drivers yield, they can assess the traffic conditions and enter safely when there is an adequate gap, reducing the chance of accidents and ensuring a smoother driving experience.

In contrast, the other choices present actions that could disrupt traffic flow or create unsafe situations. For instance, accelerating into the roundabout without yielding could lead to collisions with vehicles already navigating the roundabout. Stopping before entering could cause confusion and congestion, as vehicles behind the stopping driver might not expect them to halt at that point. Changing lanes before entering might also introduce unnecessary risks, as lanes are typically established after entering the roundabout, making it safer to adjust position once inside. Therefore, yielding to the traffic already in the roundabout is the correct and safe practice for drivers.