Bypass (road)
A bypass is a road or highway that avoids or "bypasses" a built-up area, town, or village, to let through traffic flow without interference from local traffic, to reduce congestion in the built-up area, to improve road safety and as replacement for obsolete roads that are no longer in use as a result of devastating natural disasters. A bypass specifically designated for trucks may be called a truck route.
If there are no strong land use controls, buildings are often built in town along a bypass, converting it into an ordinary town road, and the bypass may eventually become as congested as the local streets it was intended to avoid. Many businesses are often built there for ease of access, while homes are often avoided for noise and pollution reasons.
Bypass routes are often on new land where no road originally existed. This creates a conflict between those who support a bypass to reduce congestion in a built-up area and/or as replacement for roads that became obsolete and those who oppose the development of undeveloped land. A city may also oppose the project, because of the potential reduction in city core.
For other reasons, construction of bypass routes may be started if there was a research about natural disaster green zones using space satellite-based mapping first before building them.
Canada
In Ontario, examples include the Donald Cousens Parkway and the Box Grove Bypass in the city of Markham; and in Toronto a section of Highway 401 was called the Toronto Bypass in the 1950s when the highway was built as a bypass of Highway 2, Ontario Highway 2A which was built to bypass Highway 2 between Toronto and Newcastle, and the Caledonia Bypass, a section of Highway 6 in Caledonia.In Nova Scotia, the section of Highway 104 between Thomson Station and Masstown is colloquially named the Cobequid Pass; this name is for a section of road that bypasses the Wentworth Valley by crossing the Cobequid Mountains.
United Kingdom
The idea of bypasses predates the use of motor vehicles. The first London bypass, the present Marylebone Road between Paddington and Islington, was started in 1756.Bypasses can take many years to gain planning approval and funding. Many towns and villages have been campaigning for bypasses for over 30 years e.g. Banwell in North Somerset.
There was large-scale protest during construction of the Newbury bypass—officially known as the Winchester–Bicester Trunk Road —a stretch of dual carriageway which bypasses the town of Newbury in Berkshire, England. The protest was popularly known as the Third Battle of Newbury, a name which was also adopted by one of the main protest groups. The name was chosen in reference to the First Battle of Newbury of 1643 and the Second Battle of Newbury of 1644, both of which took place close to the town during the English Civil War.
United States
In the United States, bypass routes are a type of special route used on an alternative routing of a highway around a town when the main route of the highway goes through the town. The original designation of these routes were "truck routes" to divert through truck traffic away from the town, but the designation was changed to "bypass" in 1959 by AASHTO. However, many "truck" routes remain where the mainline of the highway is prohibited for trucks.In a few cases, both a bypass and a business route exist, each with auxiliary signs. Bypass routes are less common than business routes. Many of those that existed before the era of Interstate Highways have lost their old designations. For example, in Missouri, the old bypass route of U.S. Route 71 to the east of Kansas City, Missouri was decommissioned as Interstate 435 supplanted it; the remainder that existed as suburban surface route became Missouri Route 291. Around St. Louis, Missouri, what had been U.S. Route 50 Bypass was absorbed into a diversion of U.S. Route 50 from Interstate 44 and Interstate 64.
File:Interstate 95 - Virginia.jpg|thumb|Overhead sign along Interstate 95 displaying Interstate 295 as a bypass route for Richmond, Virginia
In the Interstate Highway System in the United States, primary routes are designated with a one- or two-digit number, while bypasses and loops are generally designated with a three-digit number beginning with an even digit. However, there are many exceptions to this convention, where routes with three-digit numbers serve the main route through town while the routes with one- or two-digit numbers serve as the bypass. A few such examples can be found in the metropolitan areas of Des Moines, Iowa, Omaha, Nebraska, and Pittsburgh, Pennsylvania.
Another meaning of the term bypass route is a highway that was constructed to bypass an area that is often congested with traffic. This includes Interstate Highway beltways and U.S. Highways constructed to circumvent downtown areas. Examples of these are U.S. Route 60 bypassing Williamsburg, Virginia, Interstate 285 bypassing Downtown Atlanta, U.S. Route 20/U.S. Route 31 bypassing metro South Bend, Indiana, and Interstate 75 bypassing Tampa and St. Petersburg, Florida. These bypasses usually carry mainline routes rather than auxiliary "bypass" routes.
The first bypass route in the United States was completed in 1958 as Alabama State Route 210 in Dothan, Alabama.