Several systems of land transport have been devised, from the most basic system of humans carrying things from place to sophisticated networks of ground-based transportation using different types of vehicles and infrastructure. The three types are human-powered, animal powered and machine powered
Human-powered transportation remains common in developing countries. Human-powered transport, a form of
sustainable transportation, is the transport of people and/or goods using
human muscle-power, in the form of
walking,
running and
swimming. Modern
technology has allowed
machines to enhance human power. Human-powered transport remains popular for reasons of cost-saving,
leisure,
physical exercise, and
environmentalism; it is sometimes the only type available, especially in underdeveloped or inaccessible regions. Although humans are able to walk without infrastructure, the transport can be enhanced through the use of roads, especially when using the human power with vehicles, such as bicycles and
inline skates. Human-powered vehicles have also been developed for difficult environments, such as snow and water, by
watercraft rowing and
skiing; even the air can be entered with
human-powered aircraft.
Animal-powered transportation Animal-powered transport is the use of
working animals for the movement of people and goods. Humans may ride some of the animals directly, use them as
pack animals for carrying goods, or harness them, alone or in
teams, to pull
sleds or wheeled
vehicles.
Road transportation is often heavily congested at rush hour in
Downtown Los Angeles. A road is an identifiable
route, way or
path between two or more
places. Roads are typically smoothed,
paved, or otherwise prepared to allow easy travel; though they need not be, and historically many roads were simply recognizable routes without any formal
construction or
maintenance. In
urban areas, roads may pass through a
city or
village and be named as
streets, serving a dual function as urban space
easement and route. The most common road vehicle is the
automobile; a
wheeled passenger vehicle that carries its own
motor. Other users of roads include
buses,
trucks,
motorcycles,
bicycles and
pedestrians. As of 2002, there were 590 million automobiles worldwide. Road transport offers a complete freedom to road users to transfer the vehicle from one lane to the other and from one road to another according to the need and convenience. This flexibility of changes in location, direction, speed, and timings of travel is not available to other modes of transport. It is possible to provide door to door service only by road transport. Automobiles offer high flexibility and with low capacity, but are deemed with high energy and area use, and the main source of
noise and
air pollution in cities; buses allow for more efficient travel at the cost of reduced flexibility. Road transport by truck is often the initial and final stage of freight transport.
Rail transportation , a German
high-speed passenger train|alt=White electric train with red cheatline emerging from tunnel in the countryside Rail transport is where a
train runs along a set of two parallel steel
rails, known as a railway or railroad. The rails are anchored
perpendicular to
ties (or sleepers) of timber, concrete or
steel, to maintain a consistent distance apart, or
gauge. The rails and perpendicular beams are placed on a foundation made of concrete or compressed
earth and
gravel in a bed of ballast. Alternative methods include
monorail and
maglev. A train consists of one or more connected vehicles that run on the rails. Propulsion is commonly provided by a
locomotive, that hauls a series of unpowered cars, that can carry passengers or freight. The locomotive can be powered by
steam,
diesel or by
electricity supplied by
trackside systems. Alternatively, some or all the cars can be powered, known as a
multiple unit. Also, a train can be powered by
horses,
cables,
gravity,
pneumatics and
gas turbines. Railed vehicles move with much less friction than rubber tires on paved roads, making trains more
energy efficient, though not as efficient as ships.
Intercity trains are long-haul services connecting cities; modern
high-speed rail is capable of speeds up to , but this requires specially built track.
Regional and
commuter trains feed cities from suburbs and surrounding areas, while intra-urban 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.
Other modes for
crude oil|alt=Oil pipeline winding through cold Alaskan country-side. In the background are mountains, partly snow-capped
Pipeline transport sends goods through a
pipe; most commonly liquid and gases are sent, but
pneumatic tubes can also send solid capsules using compressed air. For liquids/gases, any chemically stable liquid or gas can be sent through a pipeline. Short-distance systems exist for
sewage,
slurry, water, and
beer, while long-distance networks are used for
petroleum and
natural gas.
Cable transport is a broad mode where vehicles are pulled by
cables instead of an internal power source. It is most often used on steep slopes. Typical solutions include
aerial tramways,
elevators,
escalator and
ski lifts; some of these are also categorized as
conveyor transport.
Connections with other modes Airports Airports serve as a station for
air transport activities, but most people and cargo transported by air must use ground transport to reach their final destination.
Airport-based services are sometimes used to shuttle people to nearby
hotels or
motels when overnight stay is required for connecting
flights.
Companies provide
rental cars, private
bus and
taxi services while
mass transportation is usually provided by a
municipality or other source of
public funding. Several major airports, including
Denver International and
JFK International, provide many types of ground transportation, often by working with livery companies and similar
businesses. Smaller airports may only have a few private rental companies and a bus service. Larger airports tend to offer several different transportation options, such as light rail and/or roads that loop around an airport to provide access from multiple
terminals.
Seaports As with space transport,
sea transport typically requires use of ground transport at either end of travel for people or goods to reach their final destinations. Significant infrastructure is used at ports to transfer people and goods between sea and land systems. ==Elements==