What do we call roads that encircle a city?

Ring roads are specifically designed to encircle a city, serving as a bypass for traffic that doesn't need to enter the urban center. They help in managing congestion by providing an alternative route for vehicles, especially for those traveling between different areas without going through the city itself. This facilitates smoother traffic flow, reduces urban traffic jams, and minimizes pollution in the city center.

Other terms like highways might suggest major roads but do not necessarily imply that they encircle a city. Outer roads and perimeter roads can be used in various contexts but do not specifically denote a road system designed primarily to redirect traffic around a city. Therefore, ring roads are the most precise term for these encircling routes.