Exit numbers in the United States

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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.

[edit] Interstate Highways

Old mile tabs on I-295 in Rhode Island; several other New England states and Colorado did this. As of 2007-09-13, these signs have been replaced and only use the exit number scheme

The use of exit numbers on the Interstate Highway System became mandatory in 1971. 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 IH/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.^[1] Eleven U.S. states still use sequential numbering schemes:

• Alaska - only numbers exits on the Johansen Expressway in Fairbanks. It is unknown if they are mile-based or sequential.
• Connecticut - All sequential. Several non-Interstate freeways have interchanges without exit numbers.
• Delaware - On I-95, I-495, and Delaware Route 141 only. Delaware Route 1 formerly had a kilometer-based system (now completely converted to milemarkers), and I-295 has no exit numbers at all.
• District of Columbia - Does not post junction numbers, though some maps indicate mile based numbers on the Anacostia Freeway (Interstate 295).
• Massachusetts - All sequential (experimented with dual exit/mile tabs in the 1970s).
• Maryland - The Baltimore Beltway is sequentially numbered.^[2]
• New Hampshire - All sequential.
• New Jersey - On the New Jersey Turnpike and Palisades Interstate Parkway only; the Atlantic City Expressway, Garden State Parkway, and all Interstate highways have mile-based exits. The Brigantine Connector in Atlantic City uses letters for exits.
• New York - All sequential, except I-890 in Schenectady.^[3] Until 2000, Interstate 95 in New York City used mile-based numbers.
• Rhode Island - All sequential; experimented with dual exit/mile tabs in the 1970s.
• Vermont - The Vermont Route 289 Circumferential Highway has mileage-based exit numbering. All other Vermont freeways have sequential exit numbers.

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.
• Ohio - Between 1972 and 1974 (though the Ohio Turnpike continued to carry both systems until 2000).
• Mississippi - 1980s.
• Virginia - Early 1990s.
• Georgia - Began January 4, 2000^[4] (Interstate highways only).
• Pennsylvania - Began April 2001 on Interstates and all highways of the Pennsylvania Turnpike system.
• Florida - Began January 28, 2002, now complete.^[5]
• 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 - Has been debating converting to mileage-based exit numbering since 2000, with legislation in progress in the Senate, but no decision has yet been made. A conversion timetable for 2010 is currently proposed.

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.

[edit] Other highways

Exit numbering on non-Interstate highways is less consistent. For example, Texas, a state with mile-based exit numbering, uses sequential numbering on U.S. Route 75 between downtown Dallas and the Oklahoma border.

In Illinois, in the entire Illinois Tollway system, there are no numbered exits at all.

A number of small cities in Kentucky, mainly in the south-central and southeastern portions of the state, 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 — Two separate roads:
  • 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.
• 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, being Exit 15W off I-93). 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.

New York and most New England States expect Maine (which assigned exit numbers based on mileage) post junction numbers on express highways of any significant length, despite designation. Occasionally level junctions have posted numbers-this can be seen in New York and Connecticut (CT 9).

Oklahoma posts junction 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, especially those making up the Pennsylvania Turnpike system, used sequential exit numbers prior to 2001, but has since converted to the mileage-based system. The 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 junction 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.

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 junction numbers.^[6]

Wisconsin has exit numbers on the freeway and expressway portions of US 12 WIS 16, WIS 29, US 41, US 45, US 51, US 53, WIS 145 and US 151. ^[7]

[edit] Early exit numbers

• In April 1938, the New York City Department of Parks installed exit numbers on New York's parkways, specifically:
  • Grand Central Parkway - 1 at Triborough 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
  • 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.^[8]
• 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.^[9]
• 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 as you head 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.

[edit] References

[edit] Further reading

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

[edit] External links

• Florida's new exit numbers
• Georgia's new exit numbers
• New England Sine Chowda, with a few photos of old mile tabs
• Renumber New York, A site designed to share the benefits of distance based exit numbers in New York State