Formed: June 29, 1956 | Interstates: Interstate nn (I-nn) | |
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Business Loop: Business Loop Interstate nn (BL I-nn)
Interstate nn Business Loop (I-nn Bus. or I-nn BL) Business Spur: Business Spur Interstate nn (BS I-nn)
Interstate nn Business Spur (I-nn Bus. or I-nn BS) | ||
The Interstate Highway System of the United States, in addition to being a network of freeways, also includes a number of Business Routes assigned by the American Association of State Highway and Transportation Officials. The routes are signed with green shields resembling the Interstate Highway shield. The word is used instead of , and, above the number, where the state name is sometimes included, the word or appears. A business loop has both ends as its "parent", while a business spur has a "dangling end", sometimes running from the end of the Interstate to the downtown area.
As the main purpose of a Business Interstate is to serve a downtown area, it is typically routed on surface roads. Thus Business Interstates do not meet Interstate Highway standards. AASHTO does, however, apply similar standards as to new U.S. Routes, requiring a new Business Interstate to meet certain design standards. Business Interstates are also sometimes routed onto freeways that were once designated as mainline Interstates themselves (such as Interstate 40 Business in Winston-Salem, North Carolina and Interstate 80 Business in Sacramento, California).
Unlike 3-digit Interstate spurs, business Interstates can be repeated in the same state.
† Business Loop I-40 for Glenrio, Texas is actually a spur route (at the New Mexico state line it becomes a country road), but is posted as a business loop.
¹ Downtown Loop I-24 in Paducah, Kentucky was changed to Business Loop I-24 in 2002.