Exit numbers in the United States

Main article: Exit number

An exit number is a number assigned to a road junction, usually an exit from a freeway. It is usually marked on the same sign as the destinations of the exit, as well as a sign in the gore.

Interstate Highways

Old mile tabs on I-295 in Rhode Island; several other New England states and Colorado did this. As of September 2007, these signs have been replaced and use only the sequential exit number scheme

Exit numbers on Interstate 4 in Volusia County, Florida. In this case, mile-based exits 111A and 111B had been sequential exits 53CA and 53CB, as the 'OLD 53CA' tab shows.

Kilometer based exit numbers on I-19 in Arizona

The Federal Highway Administration (FHWA) generally requires exit numbers (mile-based or consecutively) on the Interstate Highway System; the FHWA established that requirement in 1970. The Manual of Uniform Traffic Control Devices (MUTCD) encouraged use of mileposts and exit numbering by 1961. The MUTCD mandated exit numbering in 1971. The FHWA granted California an exception due to the cost of installing and maintaining additional signage. California was able to obtain a waiver because it had already built most of its freeways, although some freeways in Los Angeles County received junction numbers: Interstate 10 was the only freeway in the county that had a complete set of junction numbers. Interstate 5, US 101, and then CA 11 (now I-110/CA 110) were numbered for short distances from downtown Los Angeles. Freeway connections were unnumbered, and junction numbers were only shown on plates, not on gore signs. In 2002, the Cal-NExUS program began to completely number California's junctions. The program is not well-funded, especially because of California's budget woes, so exits are only being signed with numbers when signs need to be replaced. As the efficiency of an exit numbering system for navigational purposes depends on all exits being consistently numbered, the usefulness of the system while only some exits are numbered is limited. Originally, the initial completion date for this project was set as November 2004. The deadline was then extended to 2008. However, the 2006 edition of the California MUTCD removed any sort of compliance deadline for the exit numbers.

Eleven U.S. states as of June 2008 use sequential numbering schemes, although the 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) requires these states to transition to distance-based numbering. Although a ten-year compliance date was proposed for the new edition of the MUTCD , a compliance date for this change was ultimately not adopted with the 2009 edition, meaning that the transition is accomplished through a systematic upgrading of existing signing and there is no specific date by which the change must be implemented.

• Alaska - only numbers exits on the Johansen Expressway in Fairbanks. Mile-based.
• Connecticut - All sequential. Several non-Interstate freeways have interchanges without exit numbers. The state planned to convert Interstate 91 to mileage-based exit numbering in 1974, but CONNDOT abandoned that initiative due to objections from local businesses.
• Delaware - On I-95, I-495, and Delaware Route 141 only. Delaware Route 1 uses kilometer-based exit numbers (despite using milemarkers), and I-295 has no exit numbers at all.
• District of Columbia - Historically, the only exit numbers posted in the District consisted of sequential numbers on Interstate 295. The few other freeways within the District of Columbia did not have exit numbers, but in 2008 the District began posting sequential numbers on Interstate 395. As of June 2008, not all interchanges had received numbers. The close proximity of the interchanges on this short freeway, coupled with the lack of space for new interchanges, renders the sequential system more practical than the mileage-based.
• Massachusetts - All sequential (experimented with dual exit/mile tabs in the 1970s).
• Maryland - The Baltimore Beltway is sequentially numbered.
• New Hampshire - All sequential.
• New Jersey - Sequential numbering on the New Jersey Turnpike, Palisades Interstate Parkway, and I-676; all other New Jersey exit numbering is mile-based. (The Brigantine Connector in Atlantic City uses letters for exits.) Many New Jersey freeways lack exit numbers.
• New York - Sequential, except I-890 in Schenectady. and Interstate 95 in New York City south of the Pelham Parkway.
• Rhode Island - All sequential; experimented with dual exit/mile tabs in the 1970s.
• Vermont - Route 289 (Circumferential Highway) has mileage-based exit numbering.

Most other states began with sequential numbers and switched over later. Here is a list of these switches, in the order that they happened:

• Colorado - Used dual mile/junction plates into the mid 1970s; initially used sequential numbering.
• Indiana - Around 1980.
• Iowa - May have had sequential numbers on Interstate 80 in the early 1970s. Adopted distance-based exit numbering in 1977.
• Ohio - Between 1972 and 1974 (though the Ohio Turnpike continued to carry both systems until 2000).
• New Jersey - Around 1970. The New Jersey Turnpike kept sequential exit numbering.
• Mississippi - 1980s.
• Virginia - Early 1990s. One exception is Route 267 (sequential).
• Georgia - Began January 4, 2000, now complete. (Interstate highways only).
• Pennsylvania - Began April 2001 on Interstates and all highways of the Pennsylvania Turnpike system. Prior to renumbering, junctions solely between two two-digit interstates were not numbered (for example, between I-79 and I-80). Sequential numbering skipped these junctions.
• Florida - Began January 28, 2002, now complete. However, I-110 retained its sequential exit numbers.
• California - Began January 2002. California was the only state not to require exit numbers or mileposts, because most of their highway system was built prior to the federal requirement. Before adopting statewide exit numbering, California relied on its system of county-based mileposts on all highways, without having explicitly numbered exits.
• Maine - Early 2004 (experimented with dual exit/mile tabs in the 1970s).
• New York - The state senate passed S.5358-A, sponsored by Tom Libous (R-C-I, Binghamton) on June 10, 2008. The bill directs the New York State Department of Transportation and the New York State Thruway Authority to convert the state's exit numbers from sequential to mileage-based by January 1, 2012. On April 23, 2008, the New York State Assembly began considering its own version (A10676) that was nearly identical to the bill passed in the Senate. The bill died in committee at the end of the 2008 legislative session.

Two highways (Interstate 19 in Arizona and Delaware Route 1) have metric numbering, because they were constructed during the time when the U.S. was thought to be completely converting to metric. Delaware Route 1 currently uses standard milepost when the metric-based posts were replaced. I-19 currently has all exit numbers and distances in kilometers, but speed limits in miles per hour. The road has received funding for the distances to be changed back to miles.

Other highways

Exit numbering on non-Interstate highways is less consistent. For example, Texas, which normally uses mile-based exit numbering, uses sequential numbering on U.S. Route 75 between downtown Dallas and the Oklahoma border. Similarly, the U.S. Route 54 freeway from El Paso to the New Mexico border also uses sequential exit numbering.

• Alabama only has one numbered non-interstate highway, U.S. Route 78.

• In Arizona, many of its non-interstate freeways utilize exit numbers such as the freeway loops (Arizona State Highway 101 and Arizona State Highway 202) around Phoenix, U.S. Route 60 and Arizona State Route 51.

• In Arkansas, U.S. Route 67 and State Highway 549 are the only non-interstate freeways to have exit numbers.

• Colorado does not use exit numbers on non-interstate highways. The exception is E-470 and the Northwest Parkway, which are separate toll highways.

• In Florida, the Turnpike and other expressways owned and operated by the Florida Turnpike Enterprise use distance-number exits. Toll roads under the Orlando-Orange County Expressway Authority also use distance-number exits. The Lee Roy Selmon Expressway in Tampa uses a sequential-based exit numbering system. Expressways under the authority of the Miami-Dade Expressway Authority have no exit numbers.

• Georgia does not carry exit numbers on non-interstate expressways except for Georgia State Route 400, which runs on a sequential system, and Georgia State Route 10 Loop, running on a distance-numbers system.

• In Illinois, the Illinois Tollway system has begun numbering exits. They plan to all be numbered by the end of 2010.^{[citation needed]}

• A number of small cities in Kentucky, mainly in the southeastern and south-central portions of the Commonwealth, mark traffic lights on a main commercial road with sequential numbers, usually beginning at an intersection with a primary highway:
  • Berea — KY 21, starting at the I-75 interchange until KY 21 meets US 25. Numbering continues on US 25 until the road leaves the city limits. Throughout this stretch, numbering increases as one travels north.
  • Corbin — US 25E, starting at the I-75 interchange at North Corbin and continuing for approximately 5 miles (8 km) until its intersection with KY 830 east of Corbin. Numbering increases as one travels east (which is signed as south on 25E).
  • London has two sets of numbered lights.
    • The Hal Rogers Parkway, starting at KY 192 (which is not numbered, as it is a flashing yellow light for parkway traffic instead of a fully controlled signal) and ending at US 25. Numbering increases as one travels west.
    • KY 192, starting at the I-75 interchange and increasing as one travels east until reaching the Hal Rogers Parkway.
  • Manchester — US 421, starting at the Hal Rogers Parkway and increasing as one travels north through the city.
  • Middlesboro — KY 74 through the downtown area, with numbering increasing as one travels west.
  • Monticello — KY 90, starting at the northern end of the city and increasing until exiting the city.
  • Radcliff — US 31W, also known as Dixie Highway, starting at an intersection at the city's border with Elizabethtown and increasing as one travels north until reaching the main entrance to Fort Knox.
  • Richmond also has two sets of numbered lights.
    • Business US 25 through downtown numbers lights 1-6 from KY 52 at Lancaster Avenue and the next 5 consecutive lights south. Incidentally, the lights south of the railroad tracks and north of the KY 52 multiplex are not numbered.
    • The bypass route wrapping east around Richmond starting with KY 876 (locally known as Eastern Bypass) east of I-75 exit 87, and continues onto Dr. Robert R. Martin Highway US 25/US 421 to I-75 exit 90. The traffic lights at the interstate are not numbered.
  • Somerset — US 27, starting at the northern limits of the city and increasing as one travels south. The numbering continues even after the road leaves the city limits, with the final numbered intersection occurring shortly before US 27 enters the city of Burnside.
• Minnesota distance-numbers its exits on Interstates, but leaves other freeways or expressways with unnumbered exits. The sole exception is US 52's freeway portion through Rochester, which received mileage-based exit numbers in 2004 as part of a major widening project.

• In Mississippi, exits from Interstate 69 and non-Interstate freeways are not currently numbered, with the exception of U.S. Highway 78/future Interstate 22, which received exit numbers as part of a signing replacement project in 2002.

• New Hampshire does not assign numbers to exits to Interstates (with the exception of I-393 in Concord, in which exit 15W from I-93 connected to the US 4/US 202 interchange prior to the construction of I-393). For example, I-293's southern exit from I-93 is between exits 5 and 6, but is not numbered; NH-101 eastbound, however, despite being an interstate grade freeway, is assigned Exit 7. NH-101's own exit to Interstate 95 in Hampton is between exits 12 and 13, but is also not numbered.

• In New Mexico, US 84/285 between Pojoaque and Santa Fe is the only non-Interstate highway that uses exit numbers.

• New England states, except for Maine (which assigned exit numbers based on mileage), post exit numbers on express highways of any significant length, regardless of designation. Occasionally, at-grade intersections have posted numbers - this can be seen, for example, on CT 9.

• In New York, all highways of this type use sequential numbering. In addition:

• All parkways on Long Island, except the Southern State Parkway, Heckscher State Parkway, and Northern State Parkway preface exit numbers with a one or two letter prefix indicating the parkway's name. For example, exits on the Meadowbrook Parkway are numbered M1 through M10, and exits on the Sunken Meadow Parkway are numbered SM1 through SM5. Some of these exits have a letter suffix as well (usually N, S, E, and/or W.)
• Occasionally, at-grade intersections (level junctions) have posted numbers - this can be seen, for example, on the Taconic State Parkway and the Bronx River Parkway, as well as on parts of NY 17.
• The Taconic State Parkway numbers exits and at-grade intersections sequentially by county, with a one-letter prefix indicating the county. For example, interchanges in Westchester County are prefixed with W (e.g., W5), and interchanges in Dutchess County are prefixed with D (e.g., D10).

• Various districts within the Ohio Department of Transportation have begun to employ exit numbers on non-Interstates using the south or west entrance into the state or highway beginning as the point of origin, though at least one district measures them from the south or west entrance into the respective county.

• Oklahoma posts exit numbers on its tollway system.

• Oregon originally did not post exit numbers on any of its non-Interstate freeways. In the 1990s, the Oregon Department of Transportation began numbering most sections of its freeways with mile-based exits, starting with US-26 and OR-217 west of Portland. Now, almost all freeway interchanges in Oregon are numbered, and new interchanges built are given numbers. Note that exit numbers are based on internal highway mileage, not posted route mileage; see State highways in Oregon for an explanation on the difference between the two.

• Pennsylvania's non-Interstate highways that have numbered exits are still numbered sequentially, with the exception of the toll roads that are part of the Pennsylvania Turnpike system. PA 60 was one of these roads, but the numbers were converted to the mileage-based system (and reversed) starting in November 2009 when I-376 was extended along PA 60 to Mercer County. The Pennsylvania Turnpike Northeast Extension, opened in 1957, originally had a unique system in which the mileposts were separate from that of the mainline turnpike, starting at milepost A0.0 (the mainline turnpike went from 0 to 359), but used the sequential exit numbers 31 to 39 (the mainline turnpike went from 1 to 30). Upon the conversion to the mile-based system, the mainline turnpike uses the distance of I-76 from the Ohio state line to New Jersey (as I-276), while the Northeast Extension was converted in 2000-2003 using the mileage based on the southern junction of I-476 (with I-95 in Chester), with the southernmost Northeast Extension exit being numbered as Exit 20, using the I-476 mileage instead of Exit 333A or Exit 334 on the east–west mileage, thus making the highways separate, but distinct systems despite the use of the common ticket system. Additionally, freeway sections can have independent mileposting systems that apply exclusively to the freeway: an example of this being the Robert Casey Highway-US 6 extending northeast of Scranton, which has mileposts reflecting the length of the freeway section. Conversely, the US 22 Lehigh Valley Thruway through Bethlehem has no exit numbering, but does have mileposts that reflect the appropriate distance from the state line.

• Tennessee generally does not post exit numbers on its non-Interstate freeways, with the exception of Nashville's two non-Interstate partial beltways: TN 155 (Briley Parkway) and TN 840.

• Vermont does not use the mileage-based system. There are 2 exceptions: VT 127 and VT 289 around Burlington. The numbers would have been continuous if the Chittenden County Circumferential Highway were completed. The numbers start at Manhattan Drive just north of Burlington and end at Interstate 89 near Williston.
• Washington State does not number most of its non-Interstate freeway exits. Two exceptions are SR-14 from Vancouver to Camas (since the 1990s) and SR-16 from Tacoma to near Gig Harbor (since 2006, possibly to extend along all of SR-16 to its northern terminus in Gorst), both milepost-based. It is unclear if other freeways will receive numbers in the future.

• West Virginia has only one non-interstate with exit numbers, the US 22 freeway in Weirton.

• Wisconsin has exit numbers on the freeway and expressway portions of US 12 WIS 16, WIS 29, WIS 64, US 41, US 45, US 51, US 53, WIS 145 and US 151.

Early exit numbers

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• In April 1938, the New York City Department of Parks installed exit numbers on New York's parkways, specifically:
  • Grand Central Parkway - 1 at Robert F. Kennedy Bridge to 11 at Kew Gardens, and on to 24 at Marcus Avenue, then continuing from 25 (Lakeville Road) on the Northern State Parkway (run by the Long Island State Park Commission, which also planned numbers on its other parkways)
  • Interborough Parkway (now the Jackie Robinson Parkway) - 4 at Pennsylvania Avenue to 11 at Kew Gardens (Exits 1, 2, and 3 were intended for a formerly proposed extension to Belt Parkway)
  • Henry Hudson Parkway - 1 at 72nd Street to 19 at Mosholu Parkway
  • Hutchinson River Parkway - beginning with 7 in Pelham Bay Park
• As other NYC parkways were completed, they too got numbers.
• Connecticut's Merritt Parkway (Route 15) got sequential numbers in 1948, continuing the numbers of the Hutchinson River Parkway. The parkway still uses that system, although the Hutch has gone through a renumbering since then, making the numbers jump northbound at the state line from Exit 30 to Exit 27. The remainder of Route 15's exit numbers (Wilbur Cross Parkway/Highway) continue the Merrit sequence.
• The Pennsylvania Turnpike had sequential numbers when it opened on October 1, 1940.
• The New Jersey Turnpike had sequential numbers when it opened in late 1951.
• In the early 1950s, New Jersey's Garden State Parkway opened, probably the first road to use distance-based exit numbers.
• The Gulf Freeway (US 75, later Interstate 45) in Houston, Texas had sequential numbers by 1956 The numbering scheme started at the freeway's northern end in downtown Houston, and counted up towards the southeast and Galveston.
• Massachusetts started handing out exit numbers in the 1950s to its freeways in and around the Boston area, with an uncommon system of making sure every freeway's intersection with Route 128 was an "Exit 25", numbers increasing away from Boston. Starting in 1976, these freeways started to receive more conventional numbering. As of 2007, only the US 3 freeway retains its original numbering with the older system, to avoid exit confusion with MA 3, whose northernmost non-multiplexed numbered exit is 20.

Further reading

• Signs Numbering Exits Installed on Parkways, New York Times April 24, 1938 page 26