This article is about local travel. For information on long-distance trains and buses, see Rail travel and Bus travel. For rail transportation systems which are an attraction in their own right, See urban rail adventures.
Public transportation is organized passenger transportation. It is usually provided by buses and rail systems, including rapid transit as well as light rail, funiculars, monorail, and other modes of transport.
Depending on the country, commuter rail can be virtually identical to longer-distance trains while mostly fulfilling an urban rail role. Ticketing can be integrated with railways (e.g. in Germany) or separate (e.g. in the US).
While comfort and reliability vary a lot, in Europe and East Asia, it is usually the most practical way to get around in large cities.
Most urban rail systems are part of a government-subsidized public transport network and many carry large numbers of passengers, especially in larger cities; the Tokyo system averages over 8 million a day and Shanghai almost 7 million. These systems therefore almost always cost less than taxicabs and are often both faster than driving and cheaper than paying for parking. However, there are fairly often problems with overcrowding, especially at rush hours. So as the quotable late New York Yankees baseball player Yogi Berra used to say: "Nobody goes there anymore. It's too crowded."
With oil prices generally on the rise, and political concern for environmental protection and CO<sub>2</sub> emissions becoming more and more important, almost all countries and cities that have rapid transit systems are in the process of upgrading, modernizing and expanding their networks sometimes very rapidly. Unfortunately, this can also mean construction sites that slow down traffic, and information about a public transit system can be outdated despite being only a few years or even months old.
The urban rail system is usually extended by buses, in some cases within the same ticket system. On the other hand most urban rail systems of more than token size serve the city's mainline train station(s) (often having a hub at one or several of them) and integrated tickets are becoming increasingly common. Sometimes a train ticket already includes one ride on the urban rail system of your departure and/or origin city to enable "door to door" travel. This is true for instance for all train tickets in Germany that have "+City" printed on them.
Some see the iconic maps of the New York Subway or London Underground for the first time and get intimidated. They see a mishmash of colors and can't make head or tail of it. But once it's explained to them, they get their head around it. Not only is it not that complicated, it's actually brilliant. Soon they'll be doing it like an expert, knowing where to switch lines in order to get from A to B.
Public transportation is provided by many different vehicles.
Each of these methods is used in some cities, and it is fairly common for a single city to combine several. For example, Shanghai's system mainly uses underground rail lines downtown and elevated lines in the suburbs, and it also includes an extensive bus network, a fast magnetic levitation rail line to Pudong Airport and a tram system in one suburban neighborhood.
Nearly all such systems offer convenient connections to other transport. For local travel, most metro stations have bus or tram stops nearby, some have a major terminus for buses or trams, and many have a taxi stand. For long distance travel, nearly all rapid transit systems offer convenient connections to railway stations and airports. In London, for example, all the railway terminals and Heathrow Airport are on the underground, and the other airports can be reached by trains which depart from underground stations.
There are various methods needed to get into urban rail systems in different cities. In many cases, some form of plastic card or paper ticket must be tapped, swiped, or inserted into a machine for riders to be able to enter the platform legally. In some cases there is even a physical barrier. Some systems use turnstiles as this barrier. Turnstiles come in different designs and constructions.
In other cases, it can be perfectly legal to access the platform without having first purchased a ticket, but riding the train without buying a ticket from a ticket machine on the platform and validating it by inserting it into another machine that stamps or perforates it could incur a heavy fine. This is called "honor system"; the perfect example of it is in the Prague system.
Honor and proof of payment systems are different. Ones require validation of the ticket inside the vehicle, other require tickets to be validated outside the vehicle on the station. Hudson-Bergen Light Rail in New Jersey, Select Bus Service in New York City.
Some transportation systems require formal tickets, tokens, cards (magnetic or optical, specific for each system) for entry, while in some systems - paying cash (or changes) to drive is just fine. For example, in New York City - you can pay for a bus ride by MetroCard (special magnetic card for NYC Transit), bus transfers, by credit/debit card, by smartphone which is capable of payment methods, or simply by changes - to the driver. But you can't pay cash to the drivers on NYC buses. Other transportation do systems accept cash, but may not accept other methods.
Paying for a ride is diverse, and it varies from system to system. Also, you can pay just for one ride with a single ticket/token/card smartphone, or you can buy a pass for many rides, or even for unlimited transportation access within some amount of time like week, month, quarter, etc.
There are also different ways to leave the system. Some systems require riders to tap or insert a card or ticket into a machine before leaving the system, too, while others put no impediment whatsoever in the path of departing commuters or simply require them to walk through a door or turnstile. London and Washington, DC rapid transit are perfect examples of this options.
There are all sorts of different regulations as to what you may or may not carry into a train and whether it does or does not incur an additional charge. Many subway systems allow riders to carry bicycles with them onto the train, at least outside of rush hours, but it is not always free for your bicycle to ride with you. In Berlin, for example, bicycles are welcome anytime but require a separate bicycle ticket, on penalty of a large fine. Dangerous objects such as knives might be prohibited.
Singapore's MRT is one of several South-East Asian transit systems that includes a sign showing a durian with a line through it, the quasi-international sign for "No durians allowed!" The fruit is quite tasty and is popular throughout the region, but it smells awful.
Public transport systems often have harsher rules of order than other public areas, usually banning alcoholic beverages, but this varies between different systems. Travelling with pets may be restricted: for example, some systems such as New York's require all pets to be brought in carriers, rather than merely leashed or hand-held, though small dogs that can fit in a handbag are OK as long as they stay there. In German cities such as Berlin, however, a single ticket is specifically noted to be good for one person and one dog (extra reduced-fare tickets are needed for additional dogs), and dogs need only be leashed. Regulations for service animals are quite often more liberal than regulations for pets, and form part of the national and/or local policy on the rights of disabled people.
See Urban rail adventures for urban rail systems beyond the usual. The oldest large systems in the world (the London Underground, New York City Subway, Paris Metro, Berlin U-Bahn, Moscow Metro...) have many historical stations that are masterpieces of architecture and design in their own right. For example, Paris' famous Art Nouveau station entrances, London's Art Deco ticket halls and Moscow's cathedral-like platforms are seen as integral parts of their respective cities' heritage.
Some rapid transit systems, such as Moscow and New York City have public art on permanent display, making them interesting destinations in their own right. See Stockholm Metro for a presentation.
Some systems also display short poems or excerpts from longer poems and descriptive prose in train carriages, which was started by the London Tube as "Poems on the Underground", continued by the MTA as "Poetry in Motion" on New York's Subway and adopted by other mass transit systems around the world.
Riding on systems with elevated lines can be a cheap and cheerful way of seeing the sights of a city from a good vantage point instead of forking out for a costly open-top bus or river tour. Notable examples include much of Chicago's L system, lines 2 and 6 of the Paris Metro and the Docklands Light Railway in east London.
One inherent advantage of light rail over underground systems is the better views, and there are often routes that are worth taking for the views alone.
Some rapid transit systems are well known for buskers or more formally organized performances. Among the systems where you can hear some high-quality performances by buskers in corridors are the London Tube and the Paris Metro. New York City is one of the places where there is a formal system for selecting approved performers. Every year, there are auditions at Grand Central Terminal for Music Under New York, which gives artists a chance to perform on a regular schedule without hassles by the police, while they display the official logo of the program. The London Underground also has designated sites in prominent areas where licensed buskers can perform.
Pickpocketing is common on public transportation. Follow the usual principles: Try to avoid displaying yourself as an out-of-town traveller, don't carry more baggage than you can keep track of, keep valuables near your body, and never put anything you don't want to lose in your back pants pockets or jacket pockets, only your front pants pockets or a money belt.
Another hazard of some rapid transit systems, especially in crowded trains, is molestation. It's to be expected that in very crowded systems during rush hour, people will be mashed against each other, but that is no excuse for someone to deliberately touch a stranger's private parts. Some rapid-transit systems, such as in Tokyo, Dubai and Delhi, have women-only areas. Others, like New York's, post and play announcements against molestation and advise victims not to remain silent. If you are being molested in a crowded metro car, speak up, and the rest of the passengers will generally support you.
An obvious danger is falling onto the tracks. These (or a third rail on the side) are often electrified, so touching them can be fatal. Additionally, being struck by a train is also likely considering the high frequency of services. If you accidentally drop anything onto the tracks, inform the station staff and make no attempt to retrieve the item yourself, no matter how valuable it is.
Many rapid transport systems have installed automatic doors between the platform and the tracks, such as in Seoul, Tokyo, Hong Kong and Singapore. This is done for general safety and also to prevent suicides. However, do not be surprised if some stations on a network lack such doors.
Generally speaking, if you get stuck in a train door owing to a crowded compartment, the train will not move and will open the door again. However, there have been cases, such as in Shanghai, when people have died after the train started to move whilst they were caught in the door, so you should not rely on such safety measures. This is especially important if you travel with children, whose limbs may be too thin to be detected by the system. In buses, the driver's view may be obstructed by the crowd so that a child is hard to see.
Crowding is a risk factor for all of the above. So if you have the chance, do yourself and everyone else a favor and avoid rides during rush hour (usually 07:00-09:00 and 16:00-18:00 on weekdays), or wait for a less crowded train.
Security routines on stations and on board are usually harsher than in other public places. In high-risk areas, ticket gates might have metal detectors or body searches. Staff might require ID from passengers, and forcefully eject (or even detain) passengers for intoxication, disorderly behavior, or for absence of a proper ticket.
The crowds on public transport create a risk for infectious diseases to spread through aerosols or physical contact. This has long been a concern in many countries in Asia, and became an international risk factor during the COVID-19 pandemic. As of 2021, many public transit systems require all passengers to wear a mask over their nose and mouth at all times, and you would be best advised to do so even if it's not required.
Shutdowns can be done for various reasons: renovation, security incidents, crashes, strikes or severe weather. If you have time, look through local news every morning, and the carrier's website, to learn about disruptions.
See also: Respect#Public transport
Etiquette for public transit systems varies from system to system. For instance, in non-pandemic times, while eating on the train is acceptable in London as long as you are not making a mess, consumption of food is prohibited on public transport in Hong Kong. Likewise, while it is common for people to talk on the phone in Chicago, talking on the phone is prohibited while on trains in Tokyo, though sending text messages is common.
Don't listen to loud music.
If you are going to talk on the phone, don't do so loudly.
Don't take up two seats.
Some large cities and countries have complex transportation system described in a whole article.
See Rail travel for articles on rail travel by country, in many cases including rail transportation.
Other options, such as cycling, taxis or guided tours may provide more comfort or flexibility.