Spur (Highway)

A spur route is a usually 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 another or the same major road. Both loops and spurs can be forms of a special route.

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).

The Indian National Highway system designates spur routes of the main National Highways with letter suffixes. For example, National Highway 1 has four spur routes: NH 1A, NH 1B, NH 1C, and NH 1D, the shortest of which is just 6 kilometres (3.7 mi) in length (NH 1C) and the longest is 663 kilometres (412 mi) (NH 1A). While the spur routes essentially originate at the parent National Highway, they are not merely secondary in status as some of the spur routes serve important cities in India. For example, 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: NH 5A links Paradip with its parent NH 5 and NH 7A links Tuticorin with NH 7).

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Wikipedia