Auxiliary route

Auxiliary route is a term used in road transport and highway systems to describe a shorter, alternate route that runs parallel to a main highway. Auxiliary routes are typically numbered and labeled in relation to the main highway they supplement. They are designed to relieve congestion, provide access to local areas, or serve as bypasses.

Definition

An auxiliary route is a highway or road that assists, supports, or complements a main route or primary highway. These routes are typically designated with a prefix or suffix to the number of the main route they are associated with. For example, in the United States Numbered Highway System, an auxiliary route may be designated as "U.S. Route 1 Bypass" or "U.S. Route 1 Alternate".

Types of Auxiliary Routes

There are several types of auxiliary routes, including:

• Bypasses: These routes are designed to allow traffic to avoid congested areas or other obstacles on the main route. They are often built around cities or towns.

• Business routes: These routes direct traffic into the central business district of a city or town. They are often former alignments of the main route.

• Spurs: These routes branch off from the main route and do not rejoin it. They are often used to connect the main route with a city, town, or point of interest.

• Loops: These routes branch off from the main route and rejoin it at a different point. They are often used to provide access to a specific area or region.

Numbering

The numbering of auxiliary routes varies by country and highway system. In the United States, auxiliary routes of the Interstate Highway System are numbered with a three-digit number, where the last two digits are the number of the main route. For example, Interstate 405 is an auxiliary route of Interstate 5.

See Also

• Highway systems by country
• List of auxiliary Interstate Highways
• List of business routes of the Interstate Highway System
• List of special routes of the United States Numbered Highway System