A
spur route is a short
road forming a branch from a longer, more important route (typically a major road,
freeway,
Interstate Highway or
motorway). A
bypass or
beltway is never considered a true spur route as it typically reconnects with the major road. Both loops and spurs can be forms of
special route.
Canada
Ontario
In the province of Ontario, most spur routes are designated as A or B, such as Highway 17A, or 7B. A stands for "Alternate Route", and usually links a highway to a town's central core or main attraction, while B stands for "Business Route" or "Bypass", but are used when a main highway is routed around a town and away from its former alignment. The designation of "C" was used twice (Highway 3C, and 40C), and is assumed to mean "Connector". Both highways have long since been retired and are now
county roads. There was also one road with the D designation (Highway 8D, later the original Highway 102), and this may have stood for "Diversion", as it was along the first completed
divided highway in
Canada at the time (
Cootes Drive in
Hamilton).
United States
In the US, many
Interstate Highways have spur routes when they enter a large metropolitan area. Interstate spur routes are numbered with a three-digit number. The last two digits of the number are the number of the "parent" Interstate; e.g. a spur route of
Interstate 90 could be 990, a spur route of
Interstate 5 could be 105.
Spur Interstate routes have three-digit numbers with an odd first digit. A subsidiary route either passing through a city or bypassing it and then reconnecting to a major highway would receive an even first digit, and be considered a loop rather than a spur. For example, in the case of
Interstate 5,
Interstate 105 is a spur route ending at
Los Angeles International Airport.
Spurs are also found branching from
US highways,
state routes, etc., often as extended onramps and offramps of
expressways.
There are many numbering violations in the spur route numbering system, thus the general rules above do not always apply.
United Kingdom
In the
UK, a spur route carries the same definition, but the rules for numbering it differ.
Same-number spurs
Short spurs from primary roads or motorways typically are not given a unique number, and three arms of the junction will apparently have the same number. For example, the
A14 has a same-number spur to the
A1(M) motorway at
Huntingdon in
Cambridgeshire, the
M23 motorway has one to
Gatwick Airport in
West Sussex and the
M25 has one to
Heathrow Airport. To distinguish the spur on road signs, the road it leads to is usually given - for example "Gatwick Airport (
A23)".
Unique-number spurs
Typically, slightly longer spurs, or those with intermediate
junctions of their own, are given unique numbers to distinguish them from their parent road. There is a loose numbering system for these spurs on the motorway network, not dissimilar to the US system – the road takes a three-digit number derived from that of the parent road. Examples include the
M602 motorway (spur of the
M60 and
M62 motorways),
M621 motorway (spur of the
M62 and
M1 motorways), and
M271 motorway (spur of the
M27 motorway). There are anomalous spur numbers though, for instance the
M898 motorway (spur of the
M8 motorway; number given to match with a unique A-number road) and the unique case of the
M181 motorway, a spur of a spur.
A-road spurs do not follow a noticeable numbering system; they would be impossible to assign due to the quantity of A-road numbers in use.
India
The
Indian National Highway system designates spur routes of the main National Highways with alphabets. For example,
National Highway 1 has 4 spur routes:
NH 1A,
NH 1B,
NH 1C and
NH 1D, the shortest of which is just 6 km in distance (NH 1C) and the longest is 663 km (NH 1A). While the spur routes essentially originate at the parent National Highway, they are not essentially secondary in status as some of the spur routes serve important cities in India (
Srinagar, the capital of the state of
Jammu and Kashmir is served by the spur route NH 1A). Some spur routes are specifically used to connect important Indian
ports. (e.g.
NH 5A links
Paradip with its parent
NH 5,
NH 7A links
Tuticorin with
NH 7).
See also
Category:Transport in the United KingdomCategory:Transportation in the United StatesCategory:Road transportde:Autobahnzubringerit:Raccordo autostradale