Mode of transport transport is performed by high-capacity tramways and rapid transits, often making up the backbone of a city's public transport. Freight trains traditionally used box cars, requiring manual loading and unloading of the cargo. Since the 1960s, container trains have become the dominant solution for general freight, while large quantities of bulk are transported by dedicated trains. A road is an identifiable route of travel, usually surfaced with gravel, asphalt or concrete, and supporting land passage by foot or by a number of vehicles. The most common road vehicle in the developed world is the automobile, a wheeled passenger vehicle that
Mode of transport aircraft, like autogyros and airships, are not a significant portion of air transport.) Air transport is the fastest method of transport, Commercial jets reach speeds of up to and a considerably higher ground speed if there is a jet stream tailwind, while piston-powered general aviation aircraft may reach up to or more. This celerity comes with higher cost and energy use, and aviation's impacts to the environment and particularly the global climate require consideration when comparing modes of transportation. The Intergovernmental Panel on Climate Change (IPCC) estimates a commercial jet's flight to have some 2-4 times the effect on the