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 (earthquakes, tsunamis, landslides, volcanic eruptions).

Many businesses are often built there for ease of access, while homes are often avoided for noise and pollution reasons.

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 inactive because devastating natural disasters — those who oppose the development of (often rural) undeveloped land.

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.

The first (northern) London bypass, the present Marylebone Road between Paddington and Islington, was started in 1756.

[4] In Brazil the widest and busiest bypasses are located in the state of São Paulo, and many of them intersect and merge around large cities to form ring-like systems.

Most notably the Rodoanel Mário Covas, which encircles the city of São Paulo and passes through other cities in the metropolitan area, is the largest project of such type with a planned total length of 180 km upon completion.

The Central-Wan Chai Bypass, which costs HK$28.1 billion, is a series of tunnels between Central and Causeway Bay.

Local governments usually promote construction of bypasses where the existing highway becomes heavily congested.

Bypasses are common in rural municipalities to deter through traffic from entering the poblacion or town centre.