Channelization is a traffic engineering concept that employs the use of secondary roads,

slip lane In road design, a slip lane is a road at a junction that allows road users to change roads without actually entering an intersection. Slip lanes are "helpful... for intersections designed for large buses or trucks to physically make a turn in ...

to separate certain flows of traffic from the main traffic lanes. The method came into favor in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

in the 1950s. One of the most effective and efficient methods of controlling the traffic on a highway is the adoption of high

intersection In mathematics, the intersection of two or more objects is another object consisting of everything that is contained in all of the objects simultaneously. For example, in Euclidean geometry, when two lines in a plane are not parallel, their ...

geometric design standards. Channelization is an integral part of

at-grade intersections An intersection or an at-grade junction is a junction (road), junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange (road), interchange, which uses bridges or tunnels to separate diff ...

to separate turning movements from through movements that are considered advisable. That helps greatly to reduce the intensity and frequency of loss of life and property from crashes. Proper channelization increases capacity, improves safety, provides maximum convenience, and instils driver confidence. Improper channelization has the opposite effects and may be worse than none at all. Over-channelization should be avoided because it could create confusion and worsen operations. Channelization of at-grade intersections is the separation or regulation of conflicting traffic movements into definite paths of travel by the use of

pavement marking Road surface marking is any kind of device or material that is used on a road surface in order to convey official information; they are commonly placed with road marking machines (also referred to as road marking equipment or pavement marking eq ...

s, raised islands, or other suitable means to facilitate the safe and orderly movement of both vehicles and

pedestrian A pedestrian is a person traveling on foot, by wheelchair or with other mobility aids. Streets and roads often have a designated footpath for pedestrian traffic, called the '' sidewalk'' in North American English, the ''pavement'' in British En ...

Sources

Channelization-The Design of Highway Intersections at Grade

Transportation Research Board The Transportation Research Board (TRB) is a division of the National Academies of Sciences, Engineering, and Medicine. TRB's mission is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challe ...

, 1952 (TRB Special Report #5).
Channelization-The Design of Highway Intersections at Grade

, 1962 (TRB Special Report #74). * Neuman, Timothy R. (June 1985)
Intersection Channelization Design Guide

(National Cooperative Highway Research Program Report NR279). . {{road-stub Road junction types