U.S. Route 220 in the context of "Concurrency (road)"

In a road network, a concurrency is an instance of one physical roadway bearing two or more different route numbers. The practice is often economically and practically advantageous when multiple routes must pass between a single mountain crossing or over a bridge, or through a major city, and can be accommodated by a single right-of-way. Each route number is typically posted on highways signs where concurrencies are allowed, while some jurisdictions simplify signage by posting one priority route number on highway signs. In the latter circumstance, other route numbers disappear when the concurrency begins and reappear when it ends. In most cases, each route in a concurrency is recognized by maps and atlases.