The following Interstates have business loops/spurs or have Business U.S. or State Routes that act as de facto Interstate business connections. Click on the Interstate to view the list of business routes:
The lists show all the Interstate business routes, both alive and dead. In the table, "decommissioned" denotes business routes no longer in service, "active" denotes active business routes, "not a business loop" denotes business routes that have never existed (such as Business U.S. routes that have both endpoints at an Interstate highway), "proposed" indicates the business route may have been proposed at one time (or is still proposed now), "remnant signage" means the business route used to exist yet still has a straggler sign or two left from its former designation; "unsigned" means the loop or spur is officially recgnized but is not signed in the field, and a "?" indicates we are not sure if the business route ever existed or not. An error business route (former California 54 in El Cajon) uses an Interstate business shield route marker (and should have used a state highway sign with a "business" banner).
The following primary Interstates do not currently have and have never had green-shielded Interstate Business Loops or Spurs. Interstate 64 is the longest route not to have any business route connections including business loops and business spurs.
- Interstate 2
- Interstate 12
- Interstate 16
- Interstate 37
- Interstate 39
- Interstate 41
- Interstate 43
Purposes of Interstate Business Loops and Spurs
Interstate business connections (loops and spurs) were approved by AASHTO in 1964 as a method to provide access from the Interstate superhighway to the cities and towns bypassed by the freeway. AASHTO made this decision during the height of Interstate highway system construction. While primarily geared toward U.S. Highway business routes, AASHTO Policy HO1 defines a business route as "a route principally within the corporate limits of a city which provides the traveling public an opportunity to travel through that city, passing through the business part of the city, while the regular number is used to obviate passing through the congested part of the city. This 'Business Route' connects with the regular numbered route at the opposite side of the city limits. 'Business Route' numbering shall be established by the placing of a standard strip carrying the words 'Business Route' on the staff above the U.S. shield." In the case of Interstate Business Loops and Spurs, a special green shield was created to mark a business routes.
With business connections (loops and spurs), travelers could choose to follow the main Interstate around the populated area or travel through it via the marked business route. Each state would determine if the business connection would be feasible or necessary. Many states in the East did not designate business loops, as most of the new Interstates paralleled the old U.S. route, and such a route was not necessary. In the western states, in many places the old U.S. route was directly overlaid by the new Interstate highway. Since Interstate highways did not go directly into towns but rather around them, the business loop designation was used to allow travelers to follow the old U.S. route through town.
Gene J. Yao writes that it would be safe to suggest that Business Interstate routes are much more prevalent in the West than in the East. "That's because out West many Interstates overlaid old U.S. roads and bypassed the cities and towns along the way. With the decommissioning of the U.S. highways it was necessary to give the vestigial remainders of the roadway going through towns a route number that identified them with the Interstate (since the Interstate replaced the U.S. highway). In the East, however, many of the old U.S. routes remain. A business route designation would be redundant with the U.S. route designation. Moreover, they might cause some confusion, since most East Coast people aren't aware of the existence of the business route system and may assume that the green business loop shields actually designate the Interstate mainline. Most states [in the northeast] have avoided spending money on designating business routes with some notable exceptions: New Hampshire (former Business Loop I-89 in Lebanon), Massachusetts (former Business Spur I-495 in Lowell), and Pennsylvania (Business Loop I-83)."
Maintenance of the business route depends upon the state's preference. Some states, like Illinois, Michigan, South Dakota, and Wyoming, treat business loops as full state highways, receiving the same signage standards as "normal" Interstate, U.S., and state highways. Other states, like California, usually transfer responsibility for business loops to the local municipality when the bypass route is completed. Some other states have some business loops under local control and others under state control, including Nevada and Washington.
As the Interstate Highway System neared completion, business routes became more prevalent. Business loops were commissioned in some areas where the U.S. route still existed as a means to entice travelers to exit and use the services available in that town. However, business connections were always city arterials, meaning the business route had traffic lights, cross streets, and so on. Sometimes the sections closer to the Interstate were multi-lane divided or even access controlled, but a full freeway business connection was very uncommon.
Types of Business Routes
There are five basic types of business connections:
- Business Loops that replace a decommissioned U.S. route. Examples include:
Business Loops that are from Interstates cosigned with a U.S. Route. Examples include:
- The I-5 business loops in northern California, which replaced U.S. 99W through towns such as Woodland, Arbuckle, Williams, Willows, Orland, Red Bluff, and Redding.
- The I-15 business loops in Utah, which replaced U.S. 91 through towns such as St. George, Cedar City, Parowan, Beaver, and Nephi. Notably, most business loops in Utah are cosigned with a different state highway route number.
- The I-55 business loops in Illinois, which replaced U.S. 66 through towns such as Springfield, Bloomington-Normal, and Lincoln.
- The I-94 business loops in North Dakota, which replaced U.S. 10 through towns such as Mandan-Bismark and Fargo.
Business Loops that are from Interstates paralleled by a U.S. Route. Examples include:
- The I-25 business loops in Wyoming, which provide direct access from the Interstate to the original U.S. 87 route through towns such as Cheyenne, Wheatland, Douglas, Casper, and Buffalo.
- The I-70 business loops in Colorado, which provide direct access from the Interstate to the original U.S. 6 alignment in western Colorado (Grand Junction, Rifle, Idaho Springs) and U.S. 40 alignment in eastern Colorado (Denver, Limon).
- The I-86 business loop in Idaho, which provide direct access from the Interstate to the original U.S. 30 alignment through the town of American Falls.
Business Spurs from Interstate into City/Destination. Examples include:
- The I-75 business loops in southern Georgia, which connect to and supplement U.S. 41 through towns such as Tifton and Cordele.
- The former I-80 business loop in Nebraska, which connected to and supplemented U.S. 30 through the city of Sidney.
Business Loop Freeways. With the designation of Business Loop I-80 in Sacramento in 1981, the fifth type of business connection was created: the business loop freeway. There are currently four of them: Business Loop I-40 in Winston-Salem, North Carolina, Business Loop I-80 in Sacramento, California, and Business Loop I-85 in both Greensboro, North Carolina and Spartanburg, South Carolina. The Business I-495 Spur Freeway into Lowell, Massachusetts, is a decommissioned business spur freeway from Interstate 495 and U.S. 3 into the city.
- Business I-20 Spur from the I-20/95 junction into Florence, South Carolina.
- Business I-44 Spur into Fort Leonard Wood, Missouri.
Various states have different ways of designating business routes. The following sections show how certain states identify and designate business routes. The 2009 Manual on Uniform Traffic Control Devices (MUTCD) for Streets and Highways provides guidance on a wide variety of standards used for roads, including business routes. Page 143 provides pertinent information about business routes: "Standard: 05 Off-Interstate Business Route signs (see Figure 2D-3) shall consist of a cutout shield carrying the number of the connecting Interstate route and the words BUSINESS and either LOOP or SPUR in upper-case letters. The legend and border shall be white on a green background, and the shield shall be the same shape and dimensions as the Interstate Route sign. In no instance shall the word INTERSTATE appear on the Off-Interstate Business Route sign. Option: 06 The Off-Interstate Business Route sign may be used on a major highway that is not a part of the Interstate system, but one that serves the business area of a city from an interchange on the system. 07 When used on a green guide sign, a white square or rectangle may be placed behind the shield to improve contrast."
Interstate Business Routes in California
In California, business routes are specifically designated based on the requirements specified in the following passage from the California Highway Design Manual (revised May 2012). Chapter 20 ("Designation of Highway Routes") of the design manual indicates that by definition, a business route is a loop through a city or town rather than a spur:
|(4) Business Routes. A Business Route generally is a local street or road in a city or urban area, designated by the same route number as the through Interstate, U.S., or State highway to which it is connected, with the words "Business Route" attached to the identifying route shields. The Business Route designation provides guidance for the traveling public to leave the main highway at one end of a city or urban area, patronize local businesses, and continue on to rejoin the main route at the opposite end of the city or urban area. The Transportation System Information Program is responsible for approval of Business Route designations. Applications for Business Route designation and signing must be made by written request from the local government agency to the Chief of the Transportation System Information Program. U.S. and Interstate Business Routes require approval by the AASHTO Executive Committee.|
For example, when Interstate 5 was completed in Northern California, maintenance of the old U.S. 99W was turned over for maintenance to the counties and cities rather than Caltrans. There are some exceptions to this, such as Business Loop I-80 (U.S. 50 and California 51) in Sacramento. Most segments of old U.S. 99W were handed over to the counties and municipalities. Although there are several business loops on Interstate 5 between Sacramento and Red Bluff -- in Woodland, Arbuckle, Williams, Willows, and Orland -- we challenge anyone to find their way along the business route. The signage is usually left to the local municipality and is either poor or nonexistent.
California has standards that are unlike those of other states. Joe Rouse provided the official policy on business route signing in California from the state Traffic Manual:
The ROUTE ## BUSINESS sign may be used to direct motorists to an established U.S. or State numbered business route or an Interstate business loop from a State highway. The plate should be installed below an advance ground-mounted directional sign. The sign may be placed separately in advance of the business route if it is necessary. A NEXT RIGHT/LEFT message may be used on expressway and conventional highway installations. A NEXT EXIT message may be used on freeways.
The INTERSTATE BUSINESS LOOP sign may be used to advise motorists of an established Interstate business loop. The sign should be installed on the right on the loop. It should not be placed on the Interstate route itself. The ROUTE ## BUSINESS plate should be used for advanced signing on the Interstate route.
The BUSINESS plate, in appropriate color, may be used to indicate an alternate route that branches from a US or State sign route, passes through the business district, and rejoins the route. The plate should be placed above the ROUTE SHIELD sign. The INTERSTATE BUSINESS LOOP sign should be used on an interstate business loop. The ROUTE ## BUSINESS plate should be used for advanced signing on U.S. or State sign routes.
Finally, here is Caltrans' policy on establishing business routes per the Caltrans Traffic Manual - Section 4-04.5:
State business routes and Interstate Loops are established by the District Directors. U. S. business routes require AASHTO approval. Applications may be made by memorandum and shall include a written request for the route from those local agencies within and whose boundaries the route traverses. A sketch, preferably on letter size stationary, showing the highway relocation and the business route or loop, should be included. Submission for AASHTO approval will be made by Headquarters. Continuous business route signing shall be provided through the bypassed area and back to the highway. If a business route is approved prior to relinquishment, G55 Business plates or G31 Interstate Loop shields will be installed by Caltrans. After relinquishment, they will be installed by the local agency involved.
Interstate Business Routes in Michigan
The Michigan Department of Transportation defines business routes as follows:
- Business Loop (BL) - A business loop is a surface route that leads into a downtown business district and returns to the freeway at the other end. Frequently, the business loop is the alignment of the original highway before that highway was bypassed.
- Business Route (BR) - A business route connects the freeway or through highway with the downtown and commercial areas of a city or town. Business routes are primary arterials and begin and end on the Interstate. Business Loops and Business Spurs are types of Business Routes. Business Loop implies that the business route will return to the parent route, while a business spur implies that the business route will only spur into the commercial area and not return to the parent route.
- Business Spur - A business spur is a surface street route leading from the Interstate highway into the central commercial district. The spur route ends upon reaching a specified point within that urban area.
Interstate Business Routes in Utah
Utah also has unique standards that do not conform to other states with respects to business routes. Utah's UDOT Policy 06C-32 "Off-Interstate Business Loops and Spurs" (from 1973 and revised 2006) provides for certain minimum standards before a business route may be designated. Within the state of Utah, Off-Interstate Business Loops must:
- Be located directly off of the Interstate system in rural areas outside the boundaries of any Municipal Planning Organization (MPO)
- Follow a route where three or less interchanges serve the area
- Have a length of six miles or less
- Be traversable by all legal vehicles
- Be appropriately signed
- Connect two interchanges
Within the state of Utah, Off-Interstate Business Spurs must:
- Not exceed three miles in length
- Be traversable by all legal vehicles
- Be appropriately signed
The policy continues by stating that "Signing shall conform to the most recent edition of the Manual on Uniform Traffic Control Devices (MUTCD). The Off-Interstate Business Route signs will be placed on the Interstate interchange guide signs, and trailblazing signing will be placed along the loop or spur. Only one set of Off-Interstate Business Route signs will be placed for each direction of travel on the Interstate."
Minimum standards for motorist services are also required prior to designation of a business loop or spur in Utah. For example, at least two gas stations must be open at least 16 hours per day seven days per week. The gas stations must provide fuel, oil, water, modern sanitary facilities, drinking water, and a public telephone. Additionally, at least one restaurant that operates continuously at least 14 hours per day, seven days per week, serving three meals per day, licensed by the appropriate public agency, with modern sanitary facilities and with the primary business purpose of preparing food must be located along the business route. Finally, a motel or hotel with at least ten rooms (with private modern sanitary facilities, licensed by the appropriate public agency, with a public telephone) must be located along the Utah business route.
This policy explains why most Utah off-Interstate business route are found in the less populated areas of the state and generally not among the communities of the Wasatch Front.
This page has mostly older (pre-2006) pictures of various Business Loop and Spur routes from across the country.
Page Updated October 14, 2013.