Transport for London (TfL) is the integrated transport authority responsible for most aspects of the transport system in Greater London. It plans, operates, and maintains London's public transport network, including the Underground, Overground, buses, DLR, trams, and manages major roads and cycling infrastructure. Its investment strategy focuses on upgrading, expanding, and maintaining this network to improve capacity, reliability, and sustainability, primarily funded by fares, commercial income, and government grants.