A business route (occasionally city route) in the United States and Canada is a short special route connected to a parent numbered highway at its beginning, then routed through the central business district of a nearby city or town, and finally reconnecting with the same parent numbered highway again at its end.
Business routes always have the same number as the routes they parallel. For example, U.S. 1 Business is a loop off, and paralleling, U.S. Route 1, and Interstate 40 Business is a loop off, and paralleling, Interstate 40.
In some states, a business route is designated by adding the letter "B" after the number instead of placing a "Business" sign above it. For example, Arkansas signs US business route 71 as "US 71B". On some route shields and road signs, the word "business" is shortened to just "BUS". This abbreviation is rare and usually avoided to prevent confusion with bus routes.
Signage of business routes varies, depending on the type of route they are derived from. Business routes paralleling U.S. and state highways usually have exactly the same shield shapes and nearly the same overall appearance as the routes they parallel, with a rectangular plate reading "BUSINESS" placed above the shield (either supplementing or replacing the directional plate, depending on the preference of the road agency). In order to better identify and differentiate alternate routes from the routes they parallel, some states such as Maryland are beginning to use green shields for business routes off U.S. highways. In addition, Maryland uses a green shield for business routes off state highways with the word "BUSINESS" in place of "MARYLAND" is used for a state route.