This list includes electrified rapid transit train systems from around the world. In different countries, these systems are sometimes called subways, undergrounds, tubes, mass rapid transit (MRT), métro, or U-Bahn. As of April 10, 2026, 213 cities in 63 countries operate 948 metro lines.
Light rail, also called light rail transit (LRT), is a type of passenger transportation that uses trains based on tram technology. These trains also have some features similar to heavy rapid transit systems. The term “light rail” was first used in 1972 in the United States as an English version of the German word “Stadtbahn,” which means “city railroad.” In the United States, light rail mainly uses special tracks that are not shared with other traffic.
Bus rapid transit (BRT), also called a busway or transitway, is a type of bus service designed to carry more people, operate more reliably, and offer better quality than regular buses. A BRT system usually includes special roads for buses only and gives buses priority at intersections where they share space with other vehicles. It also includes features that help reduce delays, such as areas where passengers can board and leave quickly and pay fares without slowing down the buses.
Since the opening of the original New York City Subway line in 1904, many official groups and planners have suggested adding new parts to the subway system. The first major expansion was the Dual Contracts, which were agreements between the City of New York and the IRT and BRT. This expansion brought subway service to the outer areas of the Bronx, Brooklyn, and Queens and included the building of important lines in Manhattan.
Congestion pricing in New York City, also called the Central Business District Tolling Program or CBDTP, started on January 5, 2025. It applies to most cars traveling in the central business district of Manhattan, which is south of 61st Street. This area is known as the Congestion Relief Zone.
A Clean Air Zone (CAZ) is an area in the United Kingdom where specific steps are taken to improve air quality. A CAZ may be a charging zone or a non-charging zone. Whether a vehicle is charged for entering or traveling through a CAZ depends on the type of vehicle and its Euro standard.
A low-emission zone (LEZ) is an area where certain vehicles that produce pollution are not allowed or are limited. This helps improve air quality. Vehicles that are encouraged in these areas include bicycles, small vehicles like scooters, some vehicles that use alternative fuels, hybrid electric vehicles, plug-in hybrids, and vehicles that produce no emissions, such as all-electric cars.
On car-free days, people are encouraged by government rules or by agreement among people to travel without using cars. Some cities, such as Jakarta and Tehran, have weekly car-free days. Other car-free days happen once a year.
A car-free city is an urban area that does not allow motor vehicles. These cities use public transportation, walking, and cycling for travel instead of private cars. A “car-free zone” refers to areas within a city where motor vehicles are not allowed.
Amsterdam is famous for being a city that is very friendly to bicycles. It has many bike paths, good planning, and funding for cycling, as well as being a popular place for tourists. However, there are also problems, such as many bikes being stolen, safety issues, and crowded areas in some places.