Editing Exit number

{{short description|Number assigned to a road junction}}
{{multiple issues|{{more citations needed|date=October 2013}}
{{Primary|date=January 2024}}
{{Globalize|date=February 2025}}}}

[[Image:I-4 east exits 111A-B.jpg|thumb|right|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.]]
[[Image:I-4 west exit 58.jpg|thumb|right|upright=0.64|On a road with distance-based exit numbering, the exit number (shown here on a [[gore (road)|gore]] sign) matches a nearby mile or kilometer marker.]]
[[Image:Puerto_RICO_HGW.JPG|thumb|right|[[Puerto Rico]] is the only place in the United States that uses Spanish like the "Salida 5B" sign.]]
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. In some countries, such as the United States and Canada,<ref name=mutcd/> it is also marked on a sign in the [[gore (road)|gore]].

Exit numbers typically reset at political borders such as [[U.S. state|state]] lines.<ref name=mutcd>{{Cite book |author = Federal Highway Administration |author2 = National Committee on Uniform Traffic Control Devices |name-list-style = amp |date = May 2012 |chapter-url = https://mutcd.fhwa.dot.gov/htm/2009r1r2/part2/part2e.htm#section2E31 |chapter = Section 2E.31: Interchange Exit Numbering |title = Manual on Uniform Traffic Control Devices  |edition = Revised 2009 |location = Washington, D.C. |publisher = Federal Highway Administration |access-date = October 29, 2018|author-link = Federal Highway Administration |title-link = Manual on Uniform Traffic Control Devices }}</ref>

Some non-[[freeway]]s use exit numbers. An extreme case of this is in New York City, where the [[Grand Concourse (Bronx)|Grand Concourse]] and [[Linden Boulevard]] were given sequential numbers, one per intersection (both boulevards no longer have exit numbers as of 2011). A milder version of this has been recently used on the [[West Side Highway]], also in New York, where only the major intersections are numbered (possibly to match the planned exits on the cancelled [[Westway (New York)|Westway]] freeway). Another case is the [[Nanaimo Parkway]] in [[Nanaimo, British Columbia]], carrying [[British Columbia Highway 19|Highway 19]], where all exits are numbered though all except one are at-grade intersections. Some other intersections on Highway 19 outside Nanaimo are also given numbers.

As a means of educating motorists, some [[state highway]] maps include a brief explanation of the exit numbering system on an inset. [[Iowa Department of Transportation|Iowa DOT]] maps from the 1970s and 1990s included a picture or drawing of a [[milestone|milepost]] and briefly described how Iowa had included milepost references near interchanges on the map.

==Sequential numbers==
[[File:2020-07-07 15 49 49 View north along Interstate 95 (New Jersey Turnpike) at Exit 8 (New Jersey State Route 33, New Jersey State Route 133, Hightstown, Freehold) in East Windsor Township, Mercer County, New Jersey.jpg|thumb|left|The [[New Jersey Turnpike]] at exit 8. This interchange was opened in 1951.]]
[[File:2020-07-07 15 56 41 View north along Interstate 95 (New Jersey Turnpike) at Exit 8A (New Jersey State Route 32 TO U.S. Route 130, Jamesburg, Cranbury) in Monroe Township, Middlesex County, New Jersey.jpg|thumb|left|The New Jersey Turnpike at exit 8A several miles north of exit 8. This interchange was opened in the 1970s, which is why the suffix exists.]]
[[File:E4_Huskvarna_Södra,_2019_(01).jpg|thumb|left|An exit numbered 100 on [[European route E4]] in [[Jönköping]], [[Sweden]]. The exit numbers on E4 begin at 65 in [[Helsingborg]], and match to those on [[European route E20|E20]], of which it meets in [[Södertälje]].]]
Sequential exit numbering usually begins with exit 1 at the beginning of the road; each subsequent exit is given the next number. Letter suffixes are commonly used when new exits are added. For example, on the [[New York State Thruway]], an exit was added between 21 and 22, and was given the number 21A. Subsequently, a new exit was added between 21 and 21A, leading to the sequence 21 – 21B – 21A – 22. In [[Florida]], some new exits got the suffix C, so that if it had or acquired separate exits for the two directions, they would be 15CA and 15CB rather than 15AB. There are also occurrences of this happening on the New Jersey Turnpike; the original interchanges opened in 1951, with newer exits as recently as 1982. On the [[Baltimore Beltway]], there is an exit 12B-C ([[Maryland Route 372|MD 372]]), as well as 12A ([[U.S. Route 1 in Maryland|US 1]]). There is also an exit 8A ([[Interstate 895 (Maryland)|I-895]]) and an exit 8 ([[Maryland Route 168|MD 168]]).

Some sequential exits are renumbered (remaining sequential) due to added exits. For instance, the [[Hutchinson River Parkway]] in [[New York (state)|New York]] was renumbered so that its northernmost exit, 27, became 30. However, the [[Merritt Parkway]], which continued the Hutchinson's exit numbers in [[Connecticut]], was not renumbered. This means the [[New York State Route 120A|Route 120A]] interchange is numbered 27 in Connecticut and 30 in New York.

The [[Atlantic City-Brigantine Connector]] in [[Atlantic City, New Jersey]], uses letters (without numbers) for its exits; it has many exits in a short distance, and the [[South Jersey Transportation Authority]] may have wanted to avoid numbers, as the [[Atlantic City Expressway]]'s lowest numbers (mile-based) are in Atlantic City.

{{Clear}}

==Distance-based numbers==<!-- This section is linked from [[Distance]] -->
[[File:2019-05-27 16 23 47 View south along the outer loop of the Capital Beltway (Interstate 495) at Exit 40 (Cabin John Parkway, Glen Echo) on the edge of Bethesda and Potomac in Montgomery County, Maryland.jpg|thumb|right|Exit 40 along the [[Capital Beltway]] (I-495) circling Washington, D.C., which is located at milepost 40]]
[[Image:Quebec exit number.jpg|thumb|right|An exit sign (kilometer-based) on [[Quebec Autoroute 640]] in Quebec]]
As more highways were built, states and countries began to experiment with '''distance-based''' ('''mile-based''' or '''kilometer-based''') exit numbers. The first mile-based system known was implemented on the Garden State Parkway in New Jersey in the late 1950s. Michigan also implemented mile-based junction numbers on [[Interstate 94 in Michigan|Interstate 94]] in the 1960s. In this system, the number of miles from the beginning of the highway to the exit is used for the exit number. If two exits would end up with the same number, the numbers are sometimes modified slightly; unless there are too many in proximity, and exits are given sequential or directional suffixes, just as with sequential numbers. Distance based numbering is the norm for most highways in the United States and Canada. Many jurisdictions in North America began switching to distance based in the 1980s, with some projects still ongoing currently to convert towards a distance based system. These are further complemented by mile markers or KM markers.

An exit can be numbered by where the exit in the direction of increased mileage leaves the freeway, or by where the road that the exit serves crosses the freeway (which is occasionally ambiguous). From this number, the [[integer]] exit number can be determined by rounding up, rounding down, or rounding to the nearest integer. Many jurisdictions prefer to avoid an exit 0.{{efn-la|While the [[Federal Highway Administration|FHWA]] allows exits that are numbered "0", they do not require its use. For example, the 
[[Massachusetts Department of Transportation]]<ref>{{Cite web |title=Statewide Exit Renumbering Project Details |website=Mass.gov |url=https://www.mass.gov/info-details/statewide-exit-renumbering-project-details |access-date=2023-12-22 }}</ref> and the [[Connecticut Department of Transportation]]<ref>{{Cite web |title=Frequently Asked Questions (Exit Renumbering) |website=CT.gov |url=https://portal.ct.gov/-/media/dot/documents/dtrafficdesign/exit_renumbering_faq.pdf |access-date=2023-12-22 }}</ref> both have chosen not to incorporate these exits statewide.}} To this end, the numbers are either rounded up to get the exit number, or any exit that would get the number 0 is instead numbered 1. Examples of highways with an exit 0 are [[British Columbia Highway 1]] on the mainland, [[Interstate 70 in West Virginia|Interstate 70]] in [[Wheeling, West Virginia]], along the West Virginia–Ohio border, and [[Interstate 90 in Montana|Interstate 90]] on the Montana side of the Idaho–Montana border.<!--three examples are sufficient. this is NOT an exhaustive list; rather it is just an illustrative one.-->

Some freeways' exit number starts from an advanced number (i.e. higher than 1). One reason for starting with a number higher than 1 is that the maintaining agency expects that the highway will be extended. For example, [[Ontario Highway 400]] starts at 20 because it was expected that the southern end of the highway would extend to downtown Toronto (which was never built). Another reason to use a higher number is that the freeway is branching off from another freeway. An example is [[British Columbia Highway 5]], which branches off [[British Columbia Highway 1]] and starts at 170.

In areas that use the [[metric system]], distance-based numbers are by kilometer rather than mile. A number of highways have kilometer-based exit numbers, even in areas that typically use miles; an example of this is with [[Interstate 19]] in the US state of Arizona.

==Exit numbers by country==

===Australia===
Distance-based exit numbering is used in Queensland, although there is not a consistent approach for defining the datum. For example, exit numbers may increase from south to north or north to south.

Victoria and New South Wales have partially implemented sequential exit numbering on selected urban motorways. For instance, the M31 Hume Motorway in New South Wales has exit numbering between Prestons and Campbelltown.

===Europe===
[[Image:Autobahn Exit 1.svg|thumb|150px|Exit numbers in most countries in Continental Europe]]
Most European countries use sequential numbering schemes. Spain uses distance-based numbering on its Autovias, but not on its Autopistas. Austria, the Czech Republic, Hungary and Slovakia use distance-based schemes. A number of European countries (including the Netherlands, Belgium and France) do not number motorway intersections, apparently because one cannot "exit" the motorway there. Countries like Germany and Switzerland number interchanges, but instead of the usual exit symbol, they are given a specific interchange symbol.
[[File:Valtatie 4 Finland Oulu erkanemisviitta.jpg|thumb|upright|Exit 10 at the intersection of the highway 20 on the [[Finnish national road 4|highway 4]] ([[European route E8|E8]]/[[European route E75|E75]]) in [[Oulu|Oulu, Finland]]]]
Italy uses sequential numbering on the ring roads for some cities, including the ring road of Rome (''GRA'') and Milan (''Tangenziali''). At one time, it referred to junctions on the [[Autostrada del Sole]]<ref>{{Cite web|url=http://mryamamoto.50megs.com/Autostrada_del_sole.html|title=Autostrada Del Sole|access-date=2006-09-14|archive-url=https://archive.today/20060505011533/http://mryamamoto.50megs.com/Autostrada_del_sole.html|archive-date=2006-05-05|url-status=dead}}</ref> by number, and published same on toll tickets; though these may not have been posted on signs.

[[File:UK traffic sign 2903.svg|thumb|upright=0.7|A UK motorway sign showing a junction number (25)]]
Both the United Kingdom and the Republic of Ireland use sequential numbering systems, with the junction number indicated by a white number in a black square in the corner of signs. In the United Kingdom they are frequently referenced in the media as the number with "J" on front of it, with for example Junction 58 being referred to as "J58"; as such this abbreviated term has entered popular usage. If a junction is newly constructed to between two existing junctions, it is normally allocated the number of the lower of the two junctions, with the letter "A" attached, followed by "B", then "C" (and so on). For example, a new junction opened between Junctions 86 and 87 would become Junction 86A, and if a new junction opened between Junctions 86A and 87, it would be Junction 86B.

In the Republic of Ireland, junction numbers have existed since the opening of the first section of the [[M50 motorway (Ireland)|M50 motorway]] in 1990.{{cn|date=February 2025}} Since 2005 have been given greater prominence on road signs. With the development of the [[Motorways in the Republic of Ireland#2000–2010|inter-urban motorway network in the 2000s]], the [[National Roads Authority]] adopted a numbering scheme for the inter-urban roads that saw Junction 1 be designated as that road's junction with the M50 in most cases.{{cn|date=February 2025}} This has meant renumbering of existing junctions on some motorways, most notably the [[M7 motorway (Ireland)|M7 motorway]]. Non-motorway dual carriageways forming part of major inter-urban roads also have junction numbers; however, only grade-separated interchanges are numbered.

Countries like Germany and Denmark do not number exits on single carriageway routes that are open only to motorised traffic.

===Canada===
[[File:Quebec Sortie 155.png|thumb|An exit number on a Québec Autoroute]]
Of the provinces that have numbered exit signs on their highways, the majority either use distance based or have switched to using distance based systems. Some highways may also supplement their roads wilth kilometre-based distance markers at specific intervals on the side of the road.

*[[Ontario]] has the oldest exit number system, having started posting exit numbers sequentially in the 1960s along [[Ontario Highway 401|Highway 401]]; it switched to mile-based (distance) numbering before Canada went metric. Most short freeways do not have exit numbers, and until about 2000 (with Highways [[Ontario Highway 11|11]] and [[Ontario Highway 69|69]]/[[Ontario Highway 400|400]]), incomplete freeways also did not have exit numbers. Interchanges with multiple exits are lettered ''A-B.'' On some highways, Ontario uses KM markers on the side, such as the 401 in Northumberland County. 
*[[Quebec]] has the second oldest system; it began sequential but switched to mile-based (distance) junction numbering before the Canadian metric conversion in the mid-1970s. Unlike Ontario, Quebec uses cardinal directions for multiple exits: ''E'' ("est"), ''N'' ("nord"), ''S'' ("sud"), and ''O'' ("ouest"); an example of the latter is ''20-O'' (with a hyphen) to avoid confusion with the number. 
*[[British Columbia]] uses distance-based exit numbers on its freeways. Some highways, such as Highway 91, have kilometre marker signs on the side. 
*[[Manitoba]] has the fewest posted exit numbers. [[Manitoba Highway 1|Highway 1]] has three numbered exits. Exit numbers were first posted on the [[Perimeter Highway]] in 2001. 
*[[Alberta]] has the newest exit number system. The province started posting exit numbers on [[Alberta Highway 2|Highway 2]] in 2004, and has since extended the system to Highways [[Alberta Highway 1|1]], [[Alberta Highway 16|16]], [[Stoney Trail|201]], and [[Anthony Henday Drive|216]]. In 2006, Alberta started building roadside kilometre markers in a few highways. Spacing is typically every four kilometres.
*[[Saskatchewan]] has recently switched to using the distance based system. This started with the Regina Bypass project where distance based exits are now used on the freeway. It uses distance-based exit numbers along with exits lettered A-B for interchanges with multiple exits. On a section of [[Saskatchewan Highway 11|Highway 11]] from [[Regina, Saskatchewan|Regina]] to [[Lumsden, Saskatchewan|Lumsden]], letters "A", "B", and "C" are used sequentially as "exit letters" instead, making Saskatchewan mainly a distanced-based system that utilizes a bit of sequential lettering as well.
*[[New Brunswick]] originally started out using sequential numbering but has switched to using distance based exit signs.

Sequential numbers are used only in [[Nova Scotia]], and [[Newfoundland and Labrador]].

*[[Nova Scotia]] also numbers level junctions on designated express highways. Multiple exits at an interchange use ''N-S'', or ''E-W''. (Nova Scotia also uses ''exit 0'' where an interchange is opened "before" Exit 1.) In some instances, exit numbers are skipped, usually as the result of new sections of 4-lane divided highway opening while the old arterial highway is downgraded to a collector highway. On Highway 104, exits 2, 9, 14, 16 and 34 are skipped.
*[[Newfoundland and Labrador]] uses sequential numbering for exit signs. Controlled access freeways in the province only exist around the St John's metropolitan area.

The territories of [[Yukon Territory|Yukon]], [[Nunavut]], and [[Northwest Territories]] use no exit numbers, as there are no [[freeway]]s or [[Controlled-access highway|expressways]] in the territories.

[[Prince Edward Island]] does not use exit numbers. The only limited access highway runs between New Haven and North River (part of the Trans Canada Highway), which features two interchanges, both unnumbered. The Albany Corner interchange near [[Borden-Carleton, Prince Edward Island|Borden-Carleton]] is the only other grade-separated exit.

===Hong Kong===
{{further|Hong Kong Strategic Route and Exit Number System}}

Exit numbers were introduced to major Hong Kong routes in 2004, in conjunction with the re-organization of the route numbers. A sequential numbering scheme is used.

===Japan===
The main expressway system uses sequential numbering; Metropolitan Expressway systems also use sequential junction numbering, usually appended with the expressway number expressed thus: 5-1; 5-2, etc. There are multiple toll expressways not operated by the major national syndicates or the Metropolitan Expressway Authorities that have no junction numbering scheme.

===New Zealand===
New Zealand began introducing exit numbers in the Auckland region in 2005. It uses a distance-based numbering system. The distance to the exit is measured from the origin of the highway. That is:
* State Highway 1 (Northern and Southern Motorways) measured from the origin of SH1 at [[Cape Reinga]]
* State Highway 16 (Northwestern Motorway) measured from the origin at the Port
* State Highway 18 (Upper Harbour Motorway) measured from the origin at SH1
* State Highway 20 (Southwestern Motorway) measured from the origin at SH1

There is no exit zero. If there is an exit within 1.499&nbsp;km of the origin, Exit 1 is used. Exit 2 would be between 1.500 and 2.499&nbsp;km of the origin. Subsequent 'exit zones' are at 1&nbsp;km intervals. Letter suffixes are added at multi-exit interchanges, or where two or more exits exist within the same exit zone. For example, State Highway 1 (Southern Motorway) has an Exit 429A (Symonds St), Exit 429B (Wellesley St) and Exit 429C (Port). Instead of replacing existing ramp and link signs, the exit numbers were added as supplementary information. Thus drivers can navigate either by exit number or name. Exit numbers are only used for exits that may be used by all vehicle types. Bus- or emergency vehicle-only exits would not be numbered.

Exit numbers are not used outside the Auckland region.

===Philippines===
[[File:Philippines road sign GE4-3A.svg|thumb|right|125px|Exit gore sign in the Philippines]]
Metric distance-based numbers are used on the tollways radiating from Manila. Supplemental "A" and "B" designations are appended to signage at the ends of slip roads.

===South Africa===
Uses distance based numbering (in kilometers) on main motorways. Letter suffixes are added at multi-exit interchanges, an example being the Buccleuch interchange in [[Johannesburg]].

Exit numbers are reset on the borders of the provinces as they were until 1994. This means that exit numbering may change in the middle of a province.

One exception to the usual distance based numbering is the southern portion of the M4 in [[Durban]], which uses sequential numbering.

===Taiwan===
{{multiple image
|width = 125
|image1= Taiwan Freeway Exit Sign.gif
|caption1= Taiwan exit sign prior to 2006
|image2= Taiwan Freeway New Exit Sign.gif
|caption2= Current Taiwan exit sign
}}
[[Taiwan]] uses distance-based exit numbers in kilometers.  If two exits are located within the same kilometer mark, the Roman letters are appended to differentiate the exits.  Taiwan did experiment with sequential exit numbers with National Freeway No. 1 for a couple of years, but abandoned the experiment in 2004.

Prior to 2006, Taiwan exit signs were generally near replicas of their US counterparts.  However, the exit signs now not only indicate the distance number, but they also display the Chinese code-name for the interchange.

===United States===
{{main|Exit numbers in the United States}}

==See also==
*[[Linear referencing]]

==Notes==
{{notelist}}

==References==
{{reflist}}

[[Category:Road transport]]
[[Category:Traffic signs]]
[[Category:Geopositioning markers]]