Bus lane

A bus lane or bus only lane is a lane restricted to buses on certain days and times, and generally used to speed up public transport that would be otherwise held up by traffic congestion. Often restrictions do not apply to certain other vehicles, which may include taxis, high occupancy vehicles, motorcycles, and bicycles. Bus lanes are a central part of bus rapid transit.

Design
A bus lane is not necessarily very long, as it may only be used to bypass a single congestion point such as an intersection. Some cities have built large stretches of bus lanes amounting to a separate local road system, often called a busway system.

Entire roads can be designated as bus lanes (such as Oxford Street in London or Princes Street in Edinburgh), allowing buses, taxis and delivery vehicles only, or a contra-flow bus lane can allow buses to travel in the opposite direction to other vehicles.

Some bus lanes operate at certain times of the day only, usually during rush hour, allowing all vehicles to use the lane at other times, and it is common to have bus lanes in only one direction, such as for the main direction of the morning rush hour traffic, with the buses using normal lanes in the other direction.

Bus lanes may have separate sets of traffic signals, to allow priority at intersections.

Bus lanes may be marked in several ways. They must be demarcated by lines on the road; road signs may warn that they are bus lanes on certain days and times; descriptive text such as "BUS LANE" may be marked prominently on the road surface, particularly at the beginning and end; the road surface may have a distinctive colour. Other special-purpose lanes may similarly be marked, e.g. a cycle path may have bicycle symbols and a different coloured surface.

Enforcement
Bus lanes can become ineffective if weak enforcement allows use by unauthorized vehicles or illegal parking on them (for example in shopping areas).

In London, UK, bus lanes may also be used by motorcycles, taxis and bicycles. Any other vehicles using bus lanes during the hours of operation will be fined £130 if caught by CCTV cameras installed specifically to monitor this kind of behavior.

Major networks
Some network lengths of bus lanes in major cities, listed by buses per km of bus lane):

Criticism
The installation of bus lanes requires additional space to either be constructed (increasing the impact of the road on the surrounding area, and possibly requiring private land) or taken from existing lanes; this may reduce the capacity of the road for private vehicles. The loss of lanes is controversial with many road users when this is actually an ancillary reason (i.e. when local authorities want to explicitly combine improved public transport options with reducing or at least not improving convenience for motorists).