Public transportation is a system of transport that is used by the general public. While there are a wide variety of public transportation systems available in various regions, one thing that they all have in common is that passengers will not ride in their own vehicles. When most people think of public transportation services, they think of subway trains or buses. While these are quite prominent in many cities, public transportation also consists of things such as planes or taxicabs. While many people have the option of either driving their own vehicles or using public transportation systems in the US, public transportation has become the preferred method of travel in places such as Tokyo and London.

A common carrier will generally be responsible for the regulation of this method of travel. The vast majority of people who use public transportation services are commuting between either their homes, shopping centers, or their places of employment. Public transportation systems are an important method of travel in many developing countries, and while a large segment of people living in developed countries choose to drive their own vehicles, the increase in gas prices has prompted many people in these nations to begin using public transportation systems. Perhaps the biggest advantage to public transportation is cost. It is possible to save hundreds or even thousands of dollars each year by riding a bus or subway as opposed to driving a vehicle. The primary disadvantage to using public transportation is that an individual is limited in where they travel, and they must be ready to depart at the scheduled time.

Mass transit is the term used for transport systems that carry the general public. If one uses one's own car, this is generally not considered to be mass transit. Mass transit or public transportation most commonly involves the transportation of the public through buses, trains, trams, aeroplanes, boats and taxis; the latter is used very loosely under the 'public transport' umbrella.

Mass transit can be classified more for long journeys whereas public transport is generally used for shorter journeys. These terms are used in North America and The British Isles respectively.

Public transport runs on communal, shared vehicles on a fixed schedule without the need for a reservation. Passengers commonly travel to places where they would go everyday, and an example of this would be home, school, work, business, and shopping purposes.

Complex public transport systems are common in big cities where the principal idea is to move a lot of people around efficiently. A particular concern will also be made for demoting road congestion and reducing car pollution.

Some public transport systems are not very well developed and therefore are sometimes awkward to use, and some involve many transfers in order to get from point A to point B. Because of this, it may not be as straightforward as it seems.

By and large, public transport systems are funded wholly or partially by the government, and the revenue created from public ticket sales, advertising, and the leasing unused real estate. Nowadays, funding can also come from leasing tunnels such as the right to run fiber optic communication cables through them.