List of business routes of the Interstate Highway System

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 (AASHTO). These routes connect a central or commercial district of a city or town with an Interstate bypass, and are signed with green shields resembling the Interstate Highway shield. The word BUSINESS is used instead of INTERSTATE, and, above the number, where the state name is sometimes included, the word LOOP or SPUR 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.

Dwight D. Eisenhower National System of Interstate and Defense Highways
Interstate 24 Business markerInterstate 196 Business marker
Highway shields for Business Loop Interstate 24 and Business Spur Interstate 196
Interstate Highways in the 48 contiguous states
System information
FormedJune 29, 1956[1]
Highway names
InterstatesInterstate nn (I-nn)
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)
System links

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 have to meet Interstate Highway standards and are not considered part of the Interstate Highway System. AASHTO does, however, apply similar standards as to new U.S. Highways, requiring a new Business Interstate to meet certain design standards.[2] Business Interstates are also sometimes routed onto freeways that were once designated as mainline Interstates themselves, such as the now-decommissioned Interstate 40 Business in Winston-Salem, North Carolina, and the existing Interstate 80 Business in Sacramento, California.

Business Interstates are most often posted in the western states, across the Great Plains and in Michigan. Eastern states generally did not designate business routes, as most of the Interstates paralleled the original U.S. Highways instead of directly replacing them. With the exception of mountainous areas, this left most of the U.S. Highways in place, or as co-signed routes with the parent Interstate, while the former routes were redesignated as local or frontage roads. In contrast, construction of the Interstate system in the western states often directly overlaid the old U.S. Highway, leaving the former road impassable or as a disconnected route. Exceptions were at cities and towns, where the freeway would shift onto a bypass around them. This often left extant segments of old U.S. Highways in place, with a business route designation applied to them as a motorist aid to and from a business district of collection of motorists services.

Like auxiliary Interstate Highways, Business Interstates can be repeated from state to state along their route. However, unlike auxiliary Interstate Highways, Business Interstates can also be repeated in several locations within the same state.



Defunct routes are listed in italics.

Interstate 5Edit

Interstate 205Edit

Interstate 8Edit

Interstate 10Edit

Interstate 15Edit

Interstate 17Edit

Interstate 19Edit

Interstate 20Edit

Interstate 24Edit

¹ Downtown Loop I-24 in Paducah, Kentucky was changed to Business Loop I-24 in 2002.

Interstate 25Edit

Interstate 126Edit

Interstate 526Edit

Interstate 27Edit

Interstate 29Edit

Interstate 229Edit

Interstate 30Edit

Interstate 35Edit

Interstate 40Edit

† Business Loop I-40 for Glenrio, Texas is a spur route (at the New Mexico state line it becomes a country road), but is posted as a business loop.

Interstate 44Edit

Interstate 45Edit

Interstate 49Edit

Interstate 55Edit

Interstate 65Edit

Interstate 69Edit

Interstate 70Edit

Interstate 72Edit

Interstate 75Edit

Interstate 375Edit

Interstate 76 (west)Edit

Interstate 376Edit

Interstate 80Edit

Interstate 83Edit

Interstate 84 (east)Edit

Interstate 84 (west)Edit

Interstate 85Edit

Interstate 385Edit

Interstate 585Edit

Interstate 86 (west)Edit

Interstate 89Edit

Interstate 90Edit

Interstate 94Edit

Interstate 95Edit

Interstate 495Edit

Interstate 96Edit

Interstate 196Edit

Interstate 496Edit

Interstate 696Edit


  1. ^ Weingroff, Richard F. (Summer 1996). "Federal-Aid Highway Act of 1956, Creating the Interstate System". Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved March 16, 2012.
  2. ^ Special Committee on U.S. Route Numbering (November 15, 1997). "Report of the Special Committee on U.S. Route Numbering to the Standing Committee on Highways" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived (PDF) from the original on October 16, 2017.
  3. ^ District 11-0 (August 19, 2009). "I-376 Corridor New Exit Numbers" (PDF). Pennsylvania Department of Transportation. Retrieved November 21, 2009.[permanent dead link]

External linksEdit