Filtering forward

Lane splitting is riding a bicycle or motorcycle between lanes or rows of slow moving or stopped traffic moving in the same direction. It is sometimes called lane sharing, whitelining, filtering, or stripe-riding. This allows riders to save time, bypassing traffic congestion, and may also be safer than stopping behind stationary vehicles.

Filtering or filtering forward describes moving through traffic that is stopped. Lane splitting means riding between two lanes of vehicles, while filtering can also refer to using space on the outside edge of same-direction traffic. In Australia, the definition between filtering and splitting is based on the latter being greater than 30km/h and illegal.

In population-dense and traffic-congested urban areas, particularly in the developing world, the space between larger vehicles is filled with a wide variety of different kinds of two-wheeled vehicles, as well as pedestrians, and many other human or animal powered conveyances. In places such as Bangkok, Thailand and in Indonesia, the ability of motorcycles to take advantage of the space between cars has led to the growth of a motorcycle taxi industry. In Indonesia, the motorcycle is the most common type of vehicle.

Unlike typical developed nations that have only a handful of vehicle types on their roads, many types of transport will share the same roads as cars and trucks; this diversity is extreme in Delhi, India, where more than 40 modes of transportation regularly use the roads. In contrast, New York City, for example, has perhaps five modes, and in parts of America a vast majority of traffic is made up of two types of vehicles on the road, cars and trucks.

It has been suggested that highly diverse and adaptive modes of road use are capable of moving very large numbers of people in a given space compared with cars and trucks remaining within the bounds of marked lanes. On roads where modes of transportation are mingled this can cause a reduced efficiency for all modes.

Filtering forward, in stopped or extremely slow traffic, requires very slow speed and awareness that in a door zone, vehicle doors may unexpectedly open. Also, unexpected vehicle movements such as lane changes may occur with little warning. Buses and tractor-trailers require extreme care, as the cyclist may be nearly invisible to the drivers who may not expect someone to be filtering forward. To avoid a hook collision with a turning vehicle at an intersection after filtering forward to the intersection, cyclists are taught to either take a position directly in front of the stopped lead vehicle, or stay behind the lead vehicle. Cyclists should not stop directly at the passenger side of the lead vehicle, that being a blind spot.

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Wikipedia