Loop route
From Wikipedia, the free encyclopedia
A loop route is a highway or other major road that extends out from a typically longer, more important parents road to enter and (usually) circle a large city. A loop can function as a bypass for through traffic and also to service outlying suburbs.
Loops are prominent features in many large cities in the United States. A three-digit interstate that is a loop is usually designated by an even-digit before the number of its parent interstate. Many cites in the United States have a two-loop design where there is an outer loop, an inner loop, and interstates coming in to the city and going through the loops.
Loops are less common in the United Kingdom; there is only one loop motorway, the M621.