A classic and highly efficient example of public transportation is the Metropolitan Rapid Transit system, commonly known as the "Subway" or "Metro." These systems consist of electric-powered trains running on dedicated underground or elevated tracks, allowing them to bypass urban traffic congestion completely. In 2026, the definition of public transit has expanded to include Mobility as a Service (MaaS) models, such as autonomous electric shuttles and integrated "e-bus" networks that use AI to optimize routes in real-time. Other standard examples include city buses, light rail (trams), commuter ferries, and public bike-sharing programs. The core characteristic of public transportation is that it is shared, follows a fixed or semi-fixed schedule, and is typically funded or regulated by a government authority to ensure accessibility for all citizens. In modern "Smart Cities" of 2026, public transit is increasingly focused on "multi-modal" connectivity, where a single digital pass allows a commuter to jump from a high-speed train to an electric scooter seamlessly, significantly reducing the carbon footprint of urban travel compared to private car ownership.