Travel cards are used as a convenient and cost-effective way to pay for transportation services. However, travel cards are known by different names in different countries. In the United States, a travel card may be referred to as a MetroCard, Clipper card, or Oyster card in London. In other parts of the world, it may be called a smart card, transport card, or a transit pass. Regardless of the name, a travel card serves the same purpose - to simplify and streamline the process of paying for public transportation. They are widely used by commuters and tourists, who benefit from discounted fares and the convenience of not having to fumble with cash or tickets.