Mass transit is a form of transportation that allows many Sims to ride together, rather than having a bunch of people go in cars individually. Mass transit is expensive to set up, however, it keeps traffic down and cuts down on pollution.
SimCity had only one form of mass transit available: railroads. A rail station was available as a reward. The rail station would improve mass transit service.
SimCity 2000 added a few new options. The bus depot created a bus system affecting an area around it. Also new were subways, which worked exactly like rails except underground. The player could even attach rails and subway tunnels.
SimCity 4 made several changes. The bus system was changed to work with a system of bus stops rather than bus depots. Also, there are two types of train station in this game. One is for passengers, the other is for freight. The player also has transit mode to help them understand how Sims are traveling. The subway system also made a return to the game, albeit, worked slightly differently than the railroad network.
Rush Hour added new options to mass transit. The Grand Railroad reward was made available as well as the option of monorails and elevated rails. Elevated rails could connect to a subway system by means of a connecting piece, making both networks completely compatible with each and interchangeable.
Parking garages to increase public transit's effectiveness was also added. The player could also add ferries to get people across rivers without driving across a bridge. The player can also drive some of their public transportation vehicles in U-Drive-It mode, including a city bus, a ferry, and several types of train.