Transportation cards are smart cards used for accessing public transit systems, such as buses, trains, and subways. These cards can be loaded with money or travel passes, allowing users to pay for their rides quickly and conveniently. They often come with features like automatic reloading and discounts for frequent travelers. Many cities offer their own unique transportation cards, such as the Oyster card in London or the MetroCard in New York City. Users simply tap or swipe their cards at designated readers to enter or exit transit stations, making the process efficient and reducing the need for cash or paper tickets.