What type of route begins with an even number and travels around the city?

The type of route that begins with an even number and typically travels around a city is known as an auxiliary route. Auxiliary routes serve as secondary or supplementary roads that provide a means of bypassing urban areas, allowing for smoother traffic flow by diverting traffic from primary routes. These routes often connect with main highways and aid in managing congestion by providing alternative paths for vehicles.

In many numbering systems for roads, auxiliary routes are designated by a two-digit number prefixed with an even number, particularly in the United States. This organizational system helps drivers easily understand the structure of road networks. For example, a route like Interstate 295 might encircle a city, allowing travelers to navigate around urban centers without having to traverse through the city itself.

The other options do not fit this description: expressways are major, high-capacity roads that might not necessarily have an even-number designation or circumnavigate cities, interchanges refer to specific junctions where roads meet, and arterial roads serve as primary routes within urban areas rather than circumferential routes.