Their designation is often intended to direct traffic to the business districts bypassed when a new highway is constructed some distance away.
But within a state's transportation administration, different business routes may be assigned unique names to differentiate them.
Business routes paralleling U.S. and state highways usually have exactly the same marker 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).
Their designation as business routes is largely the product of the era of large-scale highway construction in the United States from the 1930s through the 1970s.
Typically, new highway designations carried traffic directly through the center of a given city or town.
In later development, bypasses would be constructed around the central business districts they had once passed directly through.
[9] These development patterns were the subject of frequent debate, particularly among business owners who feared the loss of customer traffic as highways took motorists away from downtown.
For example, U.S. Route 66 was for many years the primary road connecting Chicago and Los Angeles.
[10][11] While business routes frequently integrate into the street grid of their town or city, some maintain the higher-speed, limited-access design of their parent highways.