Briefly explain what a "roundabout" is.

A roundabout is defined as a circular intersection that facilitates continuous flow of traffic, where vehicles yield at entry points to traffic already circulating within the roundabout. This design promotes efficient movement by minimizing conflict points, thereby reducing the likelihood of accidents and improving traffic safety. The yield control at entry points ensures that vehicles entering the roundabout assess the flow of traffic, promoting a smoother transition and reducing the need for complete stops.

In contrast, other options refer to different traffic management elements or road designs but do not capture the specific characteristics of a roundabout. For instance, a traffic control device can encompass various tools used to manage road safety and flow, while a type of traffic signal specifically refers to devices that control vehicle movement at intersections. A road design with multiple lanes might describe general road layouts but lacks the unique traffic management features that define a roundabout.