One-way traffic in the context of "U.S. Route 20 in Indiana"

In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each direction, separated by lane markings. On multilane roadways and busier two-lane roads, lanes are designated with road surface markings. Major highways often have two multi-lane roadways separated by a median.

Some roads and bridges that carry very low volumes of traffic are less than 4.6 metres (15 ft) wide, and are only a single lane wide. Vehicles travelling in opposite directions must slow or stop to pass each other. In rural areas, these are often called country lanes. In urban areas, alleys are often only one lane wide. Urban and suburban one lane roads are often designated for one-way traffic.

Fifth Avenue is a major thoroughfare in the borough of Manhattan in New York City. The avenue runs south from West 143rd Street in Harlem to Washington Square Park in Greenwich Village. The section in Midtown Manhattan is one of the most expensive shopping streets in the world.

Fifth Avenue carries two-way traffic between 143rd and 135th Streets, and one-way traffic southbound for the rest of its route. The entire avenue carried two-way traffic until 1966. From 124th to 120th Streets, Fifth Avenue is interrupted by Marcus Garvey Park, with southbound traffic diverted around the park via Mount Morris Park West and northbound to Madison Avenue. Most of the avenue has a bus lane, but no bike lane. Fifth Avenue is the traditional route for many celebratory parades in New York City and is closed to automobile traffic on several Sundays each year.

A diode is a two-terminal electronic component that conducts electric current primarily in one direction (asymmetric conductance). It has low (ideally zero) resistance in one direction and high (ideally infinite) resistance in the other.

A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an exponential current–voltage characteristic. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used.

A turnstile (also called a gateline, baffle gate, automated gate, turn gate in some regions) is a form of gate which allows one person to pass at a time. A turnstile can be configured to enforce one-way human traffic. In addition, a turnstile can restrict passage only to people who insert a coin, ticket, transit pass, security credential, or other method of payment or verification. Modern turnstiles can incorporate biometrics, including retina scanning, fingerprints, and other individual human characteristics which can be scanned.

A turnstile can be used in the case of paid access (sometimes called a faregate or ticket barrier when used for this purpose), for example to access public transport, a pay toilet, or to restrict access to authorized people, for example in the lobby of an office building.

Charles Street, known for most of its route as Maryland Route 139 (MD 139), runs through Baltimore and the Towson area of Baltimore County. On the north end, it terminates at an intersection with Bellona Avenue near Interstate 695 (I-695). At the south end, it terminates in Federal Hill in Baltimore. Charles Street is one of the major routes through Baltimore, and is a major public transportation corridor. For the one-way portions of Charles Street, the street is functionally complemented by the parallel St. Paul Street, including St. Paul Place and Preston Gardens, Maryland Avenue, Cathedral Street, and Liberty Street.

Though not exactly at the west–east midpoint of the city, Charles Street is the dividing line between the west and east sides of Baltimore. On any street that crosses Charles Street, address numbers start from the unit block on either side, and the streets are identified as either "West" or "East," depending on whether they are to the west or east of Charles.

51st Street is a 1.9-mile (3.1 km) long one-way street traveling east to west across Midtown Manhattan.