Transport or transportation is the movement of humans, animals and goods from one location to another. In other words the action of transport is defined as a particular movement of an organism or thing from a point A to a Point B. Modes of transport include air, land (rail and road), water, cable, pipeline and space. The field can be divided into infrastructure, vehicles and operations. Transport is important because it enables trade between people, which is essential for the development of civilizations.

Transport infrastructure consists of the fixed installations, including roads, railways, airways, waterways, canals and pipelines and terminals such as airports, railway stations, bus stations, warehouses, trucking terminals, refueling depots (including fueling docks and fuel stations) and seaports. Terminals may be used both for interchange of passengers and cargo and for maintenance.

Vehicles traveling on these networks may include automobiles, bicycles, buses, trains, trucks, helicopters, watercraft, spacecraft and aircraft.

Operations deal with the way the vehicles are operated, and the procedures set for this purpose, including financing, legalities, and policies. In the transport industry, operations and ownership of infrastructure can be either public or private, depending on the country and mode.

Passenger transport may be public, where operators provide scheduled services, or private. Freight transport has become focused on containerization, although bulk transport is used for large volumes of durable items. Transport plays an important part in economic growth and globalization, but most types cause air pollution and use large amounts of land. While it is heavily subsidized by governments, good planning of transport is essential to make traffic flow and restrain urban sprawl.

Police préparant l'arrivée d'une manifestation
French National Police use several modes of transport, each with its distinct advantages and disadvantages.


Bronocice drawn
Bronocice pot with the earliest known image of a wheeled vehicle in the world, found in Poland
Bullock team
A bullock team hauling wool in Australia

Humans' first means of transport involved walking, running and swimming. The domestication of animals introduced a new way to lay the burden of transport on more powerful creatures, allowing the hauling of heavier loads, or humans riding animals for greater speed and duration. Inventions such as the wheel and the sled helped make animal transport more efficient through the introduction of vehicles. Water transport, including rowed and sailed vessels, dates back to time immemorial, and was the only efficient way to transport large quantities or over large distances prior to the Industrial Revolution.

The first forms of road transport involved animals, such as horses (domesticated in the 4th or the 3rd millennium BCE), oxen (from about 8000 BCE)[1] or humans carrying goods over dirt tracks that often followed game trails. Many early civilizations, including those in Mesopotamia and the Indus Valley, constructed paved roads. In classical antiquity, the Persian and Roman empires built stone-paved roads to allow armies to travel quickly. Deep roadbeds of crushed stone underneath kept such roads dry. The medieval Caliphate later built tar-paved roads. The first watercraft were canoes cut out from tree trunks. Early water transport was accomplished with ships that were either rowed or used the wind for propulsion, or a combination of the two. The importance of water has led to most cities that grew up as sites for trading being located on rivers or on the sea-shore, often at the intersection of two bodies of water. Until the Industrial Revolution, transport remained slow and costly, and production and consumption gravitated as close to each other as feasible.

First flight2
The Wright brothers' first flight in 1903

The Industrial Revolution in the 19th century saw a number of inventions fundamentally change transport. With telegraphy, communication became instant and independent of the transport of physical objects. The invention of the steam engine, closely followed by its application in rail transport, made land transport independent of human or animal muscles. Both speed and capacity increased rapidly, allowing specialization through manufacturing being located independently of natural resources. The 19th century also saw the development of the steam ship, which sped up global transport.

With the development of the combustion engine and the automobile around 1900, road transport became more competitive again, and mechanical private transport originated. The first "modern" highways were constructed during the 19th century with macadam. Later, tarmac and concrete became the dominant paving materials. In 1903 the Wright brothers demonstrated the first successful controllable airplane, and after World War I (1914–1918) aircraft became a fast way to transport people and express goods over long distances.[2]

After World War II (1939–1945) the automobile and airlines took higher shares of transport, reducing rail and water to freight and short-haul passenger services.[3] Scientific spaceflight began in the 1950s, with rapid growth until the 1970s, when interest dwindled. In the 1950s the introduction of containerization gave massive efficiency gains in freight transport, fostering globalization.[4] International air travel became much more accessible in the 1960s with the commercialization of the jet engine. Along with the growth in automobiles and motorways, rail and water transport declined in relative importance. After the introduction of the Shinkansen in Japan in 1964, high-speed rail in Asia and Europe started attracting passengers on long-haul routes away from the airlines.[3]

Early in U.S. history, private joint-stock corporations owned most aqueducts, bridges, canals, railroads, roads, and tunnels. Most such transport infrastructure came under government control in the late 19th and early 20th centuries, culminating in the nationalization of inter-city passenger rail-service with the establishment of Amtrak. Recently, however, a movement to privatize roads and other infrastructure has gained some ground and adherents.[5]


A mode of transport is a solution that makes use of a particular type of vehicle, infrastructure, and operation. The transport of a person or of cargo may involve one mode or several of the modes, with the latter case being called intermodal or multimodal transport. Each mode has its own advantages and disadvantages, and will be chosen for a trip on the basis of cost, capability, and route.


Sherpa carrying woods
Human-powered transport remains common in developing countries.

Human-powered transport, a form of sustainable transport, 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 transport is the use of working animals for the movement of people and commodities. 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.


A fixed-wing aircraft, commonly called airplane, is a heavier-than-air craft where movement of the air in relation to the wings is used to generate lift. The term is used to distinguish this from rotary-wing aircraft, where the movement of the lift surfaces relative to the air generates lift. A gyroplane is both fixed-wing and rotary wing. Fixed-wing aircraft range from small trainers and recreational aircraft to large airliners and military cargo aircraft.

Two things necessary for aircraft are air flow over the wings for lift and an area for landing. The majority of aircraft also need an airport with the infrastructure to receive maintenance, restocking, refueling and for the loading and unloading of crew, cargo, and passengers. While the vast majority of aircraft land and take off on land, some are capable of take-off and landing on ice, snow, and calm water.

The aircraft is the second fastest method of transport, after the rocket. Commercial jets can reach up to 955 kilometres per hour (593 mph), single-engine aircraft 555 kilometres per hour (345 mph). Aviation is able to quickly transport people and limited amounts of cargo over longer distances, but incurs high costs and energy use; for short distances or in inaccessible places, helicopters can be used.[6] As of April 28, 2009, The Guardian article notes that "the WHO estimates that up to 500,000 people are on planes at any time."[7]


Land transport covers all land-based transport systems that provide for the movement of people, goods and services. Land transport plays a vital role in linking communities to each other. Land transport is a key factor in urban planning. It consists of 2 kinds, rail and road.


ICE1 Schellenberg
InterCityExpress, a German high-speed passenger train
R160A E Train entering World Trade Center
The New York City Subway is the world's largest rapid transit system by length of routes and by number of stations.

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 operate 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;[8] modern high-speed rail is capable of speeds up to 350 km/h (220 mph), 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.


The Harbor Freeway 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.[9] Roads are typically smoothed, paved, or otherwise prepared to allow easy travel;[10] though they need not be, and historically many roads were simply recognizable routes without any formal construction or maintenance.[11] 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.[12]

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 2010, there were 1.015 billion 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 provide high flexibility with low capacity, but require high energy and area use, and are the main source of noise and air pollution in cities; buses allow for more efficient travel at the cost of reduced flexibility.[13] Road transport by truck is often the initial and final stage of freight transport.


Negombo canal 2
Built by the Dutch to transport spices, now used by the local fishermen to get to the sea, Negombo Dutch canal, Sri Lanka
Jadrolinija supetar ferry
Automobile ferry in Croatia

Water transport is movement by means of a watercraft—such as a barge, boat, ship or sailboat—over a body of water, such as a sea, ocean, lake, canal or river. The need for buoyancy is common to watercraft, making the hull a dominant aspect of its construction, maintenance and appearance.

In the 19th century, the first steam ships were developed, using a steam engine to drive a paddle wheel or propeller to move the ship. The steam was produced in a boiler using wood or coal and fed through a steam external combustion engine. Now most ships have an internal combustion engine using a slightly refined type of petroleum called bunker fuel. Some ships, such as submarines, use nuclear power to produce the steam. Recreational or educational craft still use wind power, while some smaller craft use internal combustion engines to drive one or more propellers, or in the case of jet boats, an inboard water jet. In shallow draft areas, hovercraft are propelled by large pusher-prop fans. (See Marine propulsion.)

Although it is slow compared to other transport, modern sea transport is a highly efficient method of transporting large quantities of goods. Commercial vessels, nearly 35,000 in number, carried 7.4 billion tons of cargo in 2007.[14] Transport by water is significantly less costly than air transport for transcontinental shipping;[15] short sea shipping and ferries remain viable in coastal areas.[16][17]

Other modes

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 commonly used at steep gradient. Typical solutions include aerial tramway, elevators, escalator and ski lifts; some of these are also categorized as conveyor transport.

Spaceflight is transport out of Earth's atmosphere into outer space by means of a spacecraft. While large amounts of research have gone into technology, it is rarely used except to put satellites into orbit, and conduct scientific experiments. However, man has landed on the moon, and probes have been sent to all the planets of the Solar System.

Suborbital spaceflight is the fastest of the existing and planned transport systems from a place on Earth to a distant "other place" on Earth. Faster transport could be achieved through part of a low Earth orbit, or following that trajectory even faster using the propulsion of the rocket to steer it.



GoldenGateBridge BakerBeach MC
Bridges, such as Golden Gate Bridge, allow roads and railways to cross bodies of water.

Infrastructure is the fixed installations that allow a vehicle to operate. It consists of a roadway, a terminal, and facilities for parking and maintenance. For rail, pipeline, road and cable transport, the entire way the vehicle travels must be constructed. Air and watercraft are able to avoid this, since the airway and seaway do not need to be constructed. However, they require fixed infrastructure at terminals.

Terminals such as airports, ports, and stations, are locations where passengers and freight can be transferred from one vehicle or mode to another. For passenger transport, terminals are integrating different modes to allow riders, who are interchanging between modes, to take advantage of each mode's benefits. For instance, airport rail links connect airports to the city centers and suburbs. The terminals for automobiles are parking lots, while buses and coaches can operate from simple stops.[18] For freight, terminals act as transshipment points, though some cargo is transported directly from the point of production to the point of use.

The financing of infrastructure can either be public or private. Transport is often a natural monopoly and a necessity for the public; roads, and in some countries railways and airports are funded through taxation. New infrastructure projects can have high costs and are often financed through debt. Many infrastructure owners, therefore, impose usage fees, such as landing fees at airports, or toll plazas on roads. Independent of this, authorities may impose taxes on the purchase or use of vehicles. Because of poor forecasting and overestimation of passenger numbers by planners, there is frequently a benefits shortfall for transport infrastructure projects.[19]


1992 Fiat Uno IE 1.0 Front
A Fiat Uno in 2018

A vehicle is a non-living device that is used to move people and goods. Unlike the infrastructure, the vehicle moves along with the cargo and riders. Unless being pulled/pushed by a cable or muscle-power, the vehicle must provide its own propulsion; this is most commonly done through a steam engine, combustion engine, electric motor, a jet engine or a rocket, though other means of propulsion also exist. Vehicles also need a system of converting the energy into movement; this is most commonly done through wheels, propellers and pressure.

Vehicles are most commonly staffed by a driver. However, some systems, such as people movers and some rapid transits, are fully automated. For passenger transport, the vehicle must have a compartment, seat, or platform for the passengers. Simple vehicles, such as automobiles, bicycles or simple aircraft, may have one of the passengers as a driver.


Private transport is only subject to the owner of the vehicle, who operates the vehicle themselves. For public transport and freight transport, operations are done through private enterprise or by governments. The infrastructure and vehicles may be owned and operated by the same company, or they may be operated by different entities. Traditionally, many countries have had a national airline and national railway. Since the 1980s, many of these have been privatized. International shipping remains a highly competitive industry with little regulation,[20] but ports can be public-owned.[21]


As the population of the world increases, cities grow in size and population—according to the United Nations, 55% of the world’s population live in cities, and by 2050 this number is expected to rise to 68%.[22] Public transport policy must evolve to meet the changing priorities of the urban world.[23] The institution of policy enforces order in transport, which is by nature chaotic as people attempt to travel from one place to another as fast as possible. This policy helps to reduce accidents and save lives.


Relocation of travelers and cargo are the most common uses of transport. However, other uses exist, such as the strategic and tactical relocation of armed forces during warfare, or the civilian mobility construction or emergency equipment.


ACTION Bus-467
A local transit bus operated by ACTION in Canberra, Australia

Passenger transport, or travel, is divided into public and private transport. Public transport is scheduled services on fixed routes, while private is vehicles that provide ad hoc services at the riders desire. The latter offers better flexibility, but has lower capacity, and a higher environmental impact. Travel may be as part of daily commuting, for business, leisure or migration.

Short-haul transport is dominated by the automobile and mass transit. The latter consists of buses in rural and small cities, supplemented with commuter rail, trams and rapid transit in larger cities. Long-haul transport involves the use of the automobile, trains, coaches and aircraft, the last of which have become predominantly used for the longest, including intercontinental, travel. Intermodal passenger transport is where a journey is performed through the use of several modes of transport; since all human transport normally starts and ends with walking, all passenger transport can be considered intermodal. Public transport may also involve the intermediate change of vehicle, within or across modes, at a transport hub, such as a bus or railway station.

Taxis and buses can be found on both ends of the public transport spectrum. Buses are the cheapest mode of transport but are not necessarily flexible, and taxis are very flexible but more expensive. In the middle is demand-responsive transport, offering flexibility whilst remaining affordable.

International travel may be restricted for some individuals due to legislation and visa requirements.

Medical transport

World War I ambulance Pittsburgh 20th Century Club
An ambulance from World War I

An ambulance is a vehicle used to transport people from or between places of treatment,[24] and in some instances will also provide out-of-hospital medical care to the patient. The word is often associated with road-going "emergency ambulances", which form part of emergency medical services, administering emergency care to those with acute medical problems.

Air medical services is a comprehensive term covering the use of air transport to move patients to and from healthcare facilities and accident scenes. Personnel provide comprehensive prehospital and emergency and critical care to all types of patients during aeromedical evacuation or rescue operations, aboard helicopters, propeller aircraft, or jet aircraft.[25][26]


Freight transport, or shipping, is a key in the value chain in manufacturing.[27] With increased specialization and globalization, production is being located further away from consumption, rapidly increasing the demand for transport.[28] Transport creates place utility by moving the goods from the place of production to the place of consumption. While all modes of transport are used for cargo transport, there is high differentiation between the nature of the cargo transport, in which mode is chosen.[29] Logistics refers to the entire process of transferring products from producer to consumer, including storage, transport, transshipment, warehousing, material-handling, and packaging, with associated exchange of information.[30] Incoterm deals with the handling of payment and responsibility of risk during transport.[31]

Containerization, with the standardization of ISO containers on all vehicles and at all ports, has revolutionized international and domestic trade, offering a huge reduction in transshipment costs. Traditionally, all cargo had to be manually loaded and unloaded into the haul of any ship or car; containerization allows for automated handling and transfer between modes, and the standardized sizes allow for gains in economy of scale in vehicle operation. This has been one of the key driving factors in international trade and globalization since the 1950s.[4]

Bulk transport is common with cargo that can be handled roughly without deterioration; typical examples are ore, coal, cereals and petroleum. Because of the uniformity of the product, mechanical handling can allow enormous quantities to be handled quickly and efficiently. The low value of the cargo combined with high volume also means that economies of scale become essential in transport, and gigantic ships and whole trains are commonly used to transport bulk. Liquid products with sufficient volume may also be transported by pipeline.

Air freight has become more common for products of high value; while less than one percent of world transport by volume is by airline, it amounts to forty percent of the value. Time has become especially important in regards to principles such as postponement and just-in-time within the value chain, resulting in a high willingness to pay for quick delivery of key components or items of high value-to-weight ratio.[32] In addition to mail, common items sent by air include electronics and fashion clothing.



Transport is a key component of growth and globalization, such as in Seattle, Washington, United States.

Transport is a key necessity for specialization—allowing production and consumption of products to occur at different locations. Throughout history, transport has been a spur to expansion; better transport allows more trade and a greater spread of people. Economic growth has always been dependent on increasing the capacity and rationality of transport.[33] But the infrastructure and operation of transport have a great impact on the land, and transport is the largest drainer of energy, making transport sustainability a major issue.

Due to the way modern cities and communities are planned and operated, a physical distinction between home and work is usually created, forcing people to transport themselves to places of work, study, or leisure, as well as to temporarily relocate for other daily activities. Passenger transport is also the essence of tourism, a major part of recreational transport. Commerce requires the transport of people to conduct business, either to allow face-to-face communication for important decisions or to move specialists from their regular place of work to sites where they are needed.


Transport planning allows for high utilization and less impact regarding new infrastructure. Using models of transport forecasting, planners are able to predict future transport patterns. On the operative level, logistics allows owners of cargo to plan transport as part of the supply chain. Transport as a field is also studied through transport economics, a component for the creation of regulation policy by authorities. Transport engineering, a sub-discipline of civil engineering, must take into account trip generation, trip distribution, mode choice and route assignment, while the operative level is handled through traffic engineering.

Old Market Roundabout, Bristol
The engineering of this roundabout in Bristol, United Kingdom, attempts to make traffic flow free-moving.

Because of the negative impacts incurred, transport often becomes the subject of controversy related to choice of mode, as well as increased capacity. Automotive transport can be seen as a tragedy of the commons, where the flexibility and comfort for the individual deteriorate the natural and urban environment for all. Density of development depends on mode of transport, with public transport allowing for better spatial utilization. Good land use keeps common activities close to people's homes and places higher-density development closer to transport lines and hubs, to minimize the need for transport. There are economies of agglomeration. Beyond transport, some land uses are more efficient when clustered. Transport facilities consume land, and in cities pavement (devoted to streets and parking) can easily exceed 20 percent of the total land use. An efficient transport system can reduce land waste.

Too much infrastructure and too much smoothing for maximum vehicle throughput mean that in many cities there is too much traffic and many—if not all—of the negative impacts that come with it. It is only in recent years that traditional practices have started to be questioned in many places; as a result of new types of analysis which bring in a much broader range of skills than those traditionally relied on—spanning such areas as environmental impact analysis, public health, sociology and economics—the viability of the old mobility solutions is increasingly being questioned.


Traffic jam Sao Paulo 09 2006 30
Traffic congestion persists in São Paulo, Brazil, despite the no-drive days based on license numbers.

Transport is a major use of energy and burns most of the world's petroleum. This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through emission of carbon dioxide,[34] for which transport is the fastest-growing emission sector.[35] By subsector, road transport is the largest contributor to global warming.[36]Environmental regulations in developed countries have reduced individual vehicles' emissions; however, this has been offset by increases in the numbers of vehicles and in the use of each vehicle.[34] Some pathways to reduce the carbon emissions of road vehicles considerably have been studied.[37][38] Energy use and emissions vary largely between modes, causing environmentalists to call for a transition from air and road to rail and human-powered transport, as well as increased transport electrification and energy efficiency.

Other environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. By reducing transport emissions globally, it is predicted that there will be significant positive effects on Earth's air quality, acid rain, smog and climate change.[39]

See also


  1. ^ Watts, Martin (1999). Working Oxen. Shire Album. 342. Princes Risborough, Buckinghamshire: Osprey Publishing. p. 4. ISBN 9780747804154. Retrieved 2016-02-08. [...] tamed aurochs became the first domestic oxen. The earliest evidence for domestication is found in the Middle East around ten thousand years ago.
  2. ^ Bardi, Coyle and Novack, 2006: 158
  3. ^ a b Cooper et al., 1998: 277
  4. ^ a b Bardi, Coyle and Novack, 2006: 211–14
  5. ^ Clifford Winston, Last Exit: Privatization and Deregulation of the U.S. Transportation System (Washington, D.C.: Brookings Institution, 2010).
  6. ^ Cooper et al., 1998: 281
  7. ^ Swine flu prompts EU warning on travel to US. The Guardian. April 28, 2009.
  8. ^ Cooper et al, 1998: 279
  9. ^ "Major Roads of the United States". United States Department of the Interior. 2006-03-13. Archived from the original on 13 April 2007. Retrieved 24 March 2007.
  10. ^ "Road Infrastructure Strategic Framework for South Africa". National Department of Transport (South Africa). Archived from the original on 27 September 2007. Retrieved 24 March 2007.
  11. ^ Lay, 1992: 6–7
  12. ^ "What is the difference between a road and a street?". Word FAQ. Lexico Publishing Group. 2007. Retrieved 24 March 2007.
  13. ^ Cooper et al., 1998: 278
  14. ^ The United Nations Conference on Trade and Development (UNCTAD) 2007, p. x and p. 32.
  15. ^ Stopford, 1997: 4–6
  16. ^ Stopford, 1997: 8–9
  17. ^ Cooper et al., 1998: 280
  18. ^ Cooper et al., 1998: 275–76
  19. ^ Bent Flyvbjerg, Mette K. Skamris Holm, and Søren L. Buhl, "How (In)Accurate Are Demand Forecasts in Public Works Projects", Journal of the American Planning Association 71:2, pp. 131–46.
  20. ^ Stopford, 1997: 422
  21. ^ Stopford, 1997: 29
  22. ^ Meredith, Sam (2018-05-17). "Two-thirds of global population will live in cities by 2050, UN says". CNBC. Retrieved 2018-11-20.
  23. ^ Jones, Peter (July 2014). "The evolution of urban mobility: The interplay of academic and policy perspectives". Science Direct. Retrieved November 20, 2018.
  24. ^ Skinner, Henry Alan. 1949, "The Origin of Medical Terms". Baltimore: Williams & Wilkins
  25. ^ Branas CC, MacKenzie EJ, Williams JC, Schwab CW, Teter HM, Flanigan MC, et al. (2005). "Access to trauma centers in the United States". JAMA. 293 (21): 2626–33. doi:10.1001/jama.293.21.2626. PMID 15928284.
  26. ^ Burney RE, Hubert D, Passini L, Maio R (1995). "Variation in air medical outcomes by crew composition: a two-year follow-up". Ann Emerg Med. 25 (2): 187–92. doi:10.1016/s0196-0644(95)70322-5. PMID 7832345.
  27. ^ Chopra and Meindl, 2007: 3
  28. ^ Chopra and Meindl, 2007: 63–64
  29. ^ Chopra and Meindl, 2007: 54
  30. ^ Bardi, Coyle and Novack, 2006: 4
  31. ^ Bardi, Coyle and Novack, 2006: 473
  32. ^ Chopra and Meindl, 2007: 328
  33. ^ Stopford, 1997: 2
  34. ^ a b Fuglestvet; et al. (2007). "Climate forcing from the transport sectors" (PDF). Center for International Climate and Environmental Research.
  35. ^ Worldwatch Institute (16 January 2008). "Analysis: Nano Hypocrisy?". Archived from the original on 13 October 2013. Retrieved 17 January 2008.
  36. ^ Jan Fuglestvedt; et al. (Jan 15, 2008). "Climate forcing from the transport sectors" (PDF). PNAS. doi:10.1073/pnas.0702958104.
  37. ^ "". 2009-02-17. Retrieved 2010-05-23.
  38. ^ Data on the barriers and motivators to more sustainable transport behaviour is available in the UK Department for Transport study "Climate Change and Transport Choices Archived 2011-05-30 at the Wayback Machine" published in December 2010.
  39. ^ Environment Canada. "Transportation". Archived from the original on July 13, 2007. Retrieved 30 July 2008.


External links

Auto rickshaw

An auto rickshaw (also known as a tuk-tuk) is a motorized development of the traditional pulled rickshaw or cycle rickshaw. Most have three wheels and do not tilt.

The auto rickshaw is a common form of urban transport, both as a vehicle for hire and for private use, in many countries around the world, especially those with tropical or subtropical climates, including many developing countries. Bajaj Auto of Pune, India is the world's largest auto rickshaw manufacturer.


Aviation, or air transport, refers to the activities surrounding mechanical flight and the aircraft industry. Aircraft includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as balloons and airships.

Aviation began in the 18th century with the development of the hot air balloon, an apparatus capable of atmospheric displacement through buoyancy. Some of the most significant advancements in aviation technology came with the controlled gliding flying of Otto Lilienthal in 1896; then a large step in significance came with the construction of the first powered airplane by the Wright brothers in the early 1900s. Since that time, aviation has been technologically revolutionized by the introduction of the jet which permitted a major form of transport throughout the world.


A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle designed to carry many passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-deck rigid bus, with larger loads carried by double-decker and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are used for longer-distance services. Many types of buses, such as city transit buses and inter-city coaches, charge a fare. Other types, such as elementary or secondary school buses or shuttle buses within a post-secondary education campus do not charge a fare. In many jurisdictions, bus drivers require a special licence above and beyond a regular driver's licence.

Buses may be used for scheduled bus transport, scheduled coach transport, school transport, private hire, or tourism; promotional buses may be used for political campaigns and others are privately operated for a wide range of purposes, including rock and pop band tour vehicles.

Horse-drawn buses were used from the 1820s, followed by steam buses in the 1830s, and electric trolleybuses in 1882. The first internal combustion engine buses, or motor buses, were used in 1895. Recently, interest has been growing in hybrid electric buses, fuel cell buses, and electric buses, as well as buses powered by compressed natural gas or biodiesel. As of the 2010s, bus manufacturing is increasingly globalised, with the same designs appearing around the world.

Douglas DC-3

The Douglas DC-3 is a fixed-wing propeller-driven airliner that revolutionized air transport in the 1930s and 1940s. Its lasting effect on the airline industry and World War II makes it one of the most significant transport aircraft ever produced. It has a cruise speed of 207 mph (333 km/h), capacity of 21 to 32 passengers or 6,000 lbs (2,700 kg) of cargo and a range of 1,500 mi (2,400 km).

The DC-3 is a twin-engine metal monoplane with a tailwheel-type landing gear and was developed as a larger, improved 14-bed sleeper version of the Douglas DC-2. It had many exceptional qualities compared to previous aircraft. It was fast, had good range and could operate from short runways. It was reliable and easy to maintain and carried passengers in greater comfort. Before the war it pioneered many air travel routes. It could cross the continental United States and made worldwide flights possible. It is considered the first airliner that could profitably carry just passengers.Civil DC-3 production ended in 1942 at 607 aircraft. Military versions, including the C-47 Skytrain (designated the Dakota in British Royal Air Force (RAF) service), and Russian- and Japanese-built versions, brought total production to over 16,000. Following the war, the airliner market was flooded with surplus C-47s and other ex-military transport aircraft, and Douglas' attempts to produce an upgraded DC-3 failed due to cost.

Post-war, the DC-3 was made obsolete on main routes by more advanced types such as the Douglas DC-6 and Lockheed Constellation, but the design proved exceptionally adaptable and useful. Large numbers continue to see service in a wide variety of niche roles well into the 21st century. In 2013 it was estimated that approximately 2,000 DC-3s and military derivatives were still flying, a testament to the durability of the design.

Electron transport chain

An electron transport chain (ETC) is a series of complexes that transfer electrons from electron donors to electron acceptors via redox (both reduction and oxidation occurring simultaneously) reactions, and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. This creates an electrochemical proton gradient that drives the synthesis of adenosine triphosphate (ATP), a molecule that stores energy chemically in the form of highly strained bonds. The molecules of the chain include peptides, enzymes (which are proteins or protein complexes), and others. The final acceptor of electrons in the electron transport chain during aerobic respiration is molecular oxygen although a variety of acceptors other than oxygen such as sulfate exist in anaerobic respiration.

Electron transport chains are used for extracting energy via redox reactions from sunlight in photosynthesis or, such as in the case of the oxidation of sugars, cellular respiration. In eukaryotes, an important electron transport chain is found in the inner mitochondrial membrane where it serves as the site of oxidative phosphorylation through the action of ATP synthase. It is also found in the thylakoid membrane of the chloroplast in photosynthetic eukaryotes. In bacteria, the electron transport chain is located in their cell membrane.

In chloroplasts, light drives the conversion of water to oxygen and NADP+ to NADPH with transfer of H+ ions across chloroplast membranes. In mitochondria, it is the conversion of oxygen to water, NADH to NAD+ and succinate to fumarate that are required to generate the proton gradient.

Electron transport chains are major sites of premature electron leakage to oxygen, generating superoxide and potentially resulting in increased oxidative stress.

The electron transport chain consists of a spatially separated series of redox reactions in which electrons are transferred from a donor molecule to an acceptor molecule. The underlying force driving these reactions is the Gibbs free energy of the reactants and products. The Gibbs free energy is the energy available ("free") to do work. Any reaction that decreases the overall Gibbs free energy of a system is thermodynamically spontaneous.

The function of the electron transport chain is to produce a transmembrane proton electrochemical gradient as a result of the redox reactions. If protons flow back through the membrane, they enable mechanical work, such as rotating bacterial flagella. ATP synthase, an enzyme highly conserved among all domains of life, converts this mechanical work into chemical energy by producing ATP, which powers most cellular reactions.

A small amount of ATP is available from substrate-level phosphorylation, for example, in glycolysis. In most organisms the majority of ATP is generated in electron transport chains.

Heathrow Airport

Heathrow Airport, also known as London Heathrow (IATA: LHR, ICAO: EGLL), is a major international airport in London, United Kingdom. Heathrow is the second busiest airport in the world (after Dubai International Airport) by international passenger traffic, as well as the busiest airport in Europe by passenger traffic, and the seventh busiest airport in the world by total passenger traffic. It is one of six international airports serving Greater London. In 2018, it handled a record 80.1 million passengers, a 2.7% increase from 2017 as well as 480,339 aircraft movements, an increase of 4,715 from 2017.Heathrow lies 14 miles (23 km) west of Central London, and has two parallel east–west runways along with four operational terminals on a site that covers 12.27 square kilometres (4.74 sq mi). The airport is owned and operated by Heathrow Airport Holdings, which itself is owned by FGP TopCo Limited, an international consortium led by Ferrovial that also includes Qatar Holding LLC, Caisse de dépôt et placement du Québec, GIC Private Limited, Alinda Capital Partners, China Investment Corporation and Universities Superannuation Scheme (USS). London Heathrow is the primary hub for British Airways and the primary operating base for Virgin Atlantic.

In September 2012, the Government of the United Kingdom established the Airports Commission, an independent commission chaired by Sir Howard Davies to examine various options for increasing capacity at UK airports. In July 2015, the commission backed a third runway at Heathrow, which the government approved in October 2016.

IATA airport code

An IATA airport code, also known as an IATA location identifier, IATA station code or simply a location identifier, is a three-letter code designating many airports and metropolitan areas around the world, defined by the International Air Transport Association (IATA). The characters prominently displayed on baggage tags attached at airport check-in desks are an example of a way these codes are used.

The assignment of these codes is governed by IATA Resolution 763, and it is administered by the IATA's headquarters in Montreal. The codes are published semi-annually in the IATA Airline Coding Directory.IATA also provides codes for railway stations and for airport handling entities. A list of airports sorted by IATA code is available. A list of railway station codes, shared in agreements between airlines and rail lines such as Amtrak, SNCF French Railways, and Deutsche Bahn, is available. Many railway administrations have their own list of codes for their stations, such as the list of Amtrak station codes.

International Air Transport Association

The International Air Transport Association (IATA ) is a trade association of the world’s airlines.

Consisting of 290 airlines, primarily major carriers, representing 117 countries, the IATA's member airlines account for carrying approximately 82% of total available seat miles air traffic. IATA supports airline activity and helps formulate industry policy and standards. It is headquartered in Montreal, Quebec, Canada with Executive Offices in Geneva, Switzerland.

Internet protocol suite

The Internet protocol suite is the conceptual model and set of communications protocols used in the Internet and similar computer networks. It is commonly known as TCP/IP because the foundational protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP). It is occasionally known as the Department of Defense (DoD) model because the development of the networking method was funded by the United States Department of Defense through DARPA.

The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to the scope of networking involved. From lowest to highest, the layers are the link layer, containing communication methods for data that remains within a single network segment (link); the internet layer, providing internetworking between independent networks; the transport layer, handling host-to-host communication; and the application layer, providing process-to-process data exchange for applications.

The technical standards underlying the Internet protocol suite and its constituent protocols are maintained by the Internet Engineering Task Force (IETF). The Internet protocol suite predates the OSI model, a more comprehensive reference framework for general networking systems.

List of Regional Transport Office districts in India

This is a list of the Indian Regional Transport Offices and the assigned codes for vehicle registration. These are broken down to states or Union Territories and their districts.

The offices are all belonging to a certain type:

ARTO : Additional Transport Office

AssRTO : Assistant Regional Transport Office

DTC : Deputy Transport Commissioner

DTO : District Transport Office

DyDZO : Deputy Directorate Zonal Office

DyRTO : Deputy Regional Transport Office

JtRTO : Joint Regional Transport Officer

JTC : Joint Transport Commissioner

LA : Licensing Authority

MVI : Motor Vehicle Inspector

PVD : Public Vehicles Department

RLA : Regional Licensing Authority

RTA : Regional Transport Authority

RTO : Regional Transport Office

SDivO : Subdivisional Office

SDM : Subdivisional Magistrate

SRTO : Sub Regional Transport Office

STA : State Transport Authority

UO : Unit Office

WIAA : Western India Automobile Associationin maharashtra get a new rto code no. 51-nashik rural


Logistics is generally the detailed organization and implementation of a complex operation. In a general business sense, logistics is the management of the flow of things between the point of origin and the point of consumption in order to meet requirements of customers or corporations. The resources managed in logistics may include tangible goods such as materials, equipment, and supplies, as well as food and other consumable items. The logistics of physical items usually involves the integration of information flow, materials handling, production, packaging, inventory, transportation, warehousing, and often security.

In military science, logistics is concerned with maintaining army supply lines while disrupting those of the enemy, since an armed force without resources and transportation is defenseless. Military logistics was already practiced in the ancient world and as modern military have a significant need for logistics solutions, advanced implementations have been developed. In military logistics, logistics officers manage how and when to move resources to the places they are needed.

Logistics management is the part of supply chain management that plans, implements, and controls the efficient, effective forward, and reverse flow and storage of goods, services, and related information between the point of origin and the point of consumption in order to meet customer's requirements. The complexity of logistics can be modeled, analyzed, visualized, and optimized by dedicated simulation software. The minimization of the use of resources is a common motivation in all logistics fields. A professional working in the field of logistics management is called a logistician.

London Underground

The London Underground (also known simply as the Underground, or by its nickname the Tube) is a public rapid transit system serving London, England and some parts of the adjacent counties of Buckinghamshire, Essex and Hertfordshire in the United Kingdom.The Underground has its origins in the Metropolitan Railway, the world's first underground passenger railway. Opened in January 1863, it is now part of the Circle, Hammersmith & City and Metropolitan lines; the first line to operate underground electric traction trains, the City & South London Railway in 1890, is now part of the Northern line. The network has expanded to 11 lines, and in 2017/18 carried 1.357 billion passengers, making it the world's 11th busiest metro system. The 11 lines collectively handle up to 5 million passengers a day.The system's first tunnels were built just below the surface, using the cut-and-cover method; later, smaller, roughly circular tunnels—which gave rise to its nickname, the Tube—were dug through at a deeper level. The system has 270 stations and 250 miles (400 km) of track. Despite its name, only 45% of the system is underground in tunnels, with much of the network in the outer environs of London being on the surface. In addition, the Underground does not cover most southern parts of Greater London, with fewer than 10% of the stations located south of the River Thames.The early tube lines, originally owned by several private companies, were brought together under the "UndergrounD" brand in the early 20th century and eventually merged along with the sub-surface lines and bus services in 1933 to form London Transport under the control of the London Passenger Transport Board (LPTB). The current operator, London Underground Limited (LUL), is a wholly owned subsidiary of Transport for London (TfL), the statutory corporation responsible for the transport network in Greater London. As of 2015, 92% of operational expenditure is covered by passenger fares. The Travelcard ticket was introduced in 1983 and Oyster, a contactless ticketing system, in 2003. Contactless card payments were introduced in 2014, the first public transport system in the world to do so.The LPTB was a prominent patron of art and design, commissioning many new station buildings, posters and public artworks in a modernist style. The schematic Tube map, designed by Harry Beck in 1931, was voted a national design icon in 2006 and now includes other TfL transport systems such as the Docklands Light Railway, London Overground, Crossrail (which is officially called Elizabeth Line) and Tramlink. Other famous London Underground branding includes the roundel and Johnston typeface, created by Edward Johnston in 1916.

Public transport

Public transport (also known as public transportation, public transit, or mass transit) is transport of passengers by group travel systems available for use by the general public, typically managed on a schedule, operated on established routes, and that charge a posted fee for each trip. Examples of public transport include city buses, trolleybuses, trams (or light rail) and passenger trains, rapid transit (metro/subway/underground, etc.) and ferries. Public transport between cities is dominated by airlines, coaches, and intercity rail. High-speed rail networks are being developed in many parts of the world.

Most public transport systems run along fixed routes with set embarkation/disembarkation points to a prearranged timetable, with the most frequent services running to a headway (e.g.: "every 15 minutes" as opposed to being scheduled for any specific time of the day). However, most public transport trips include other modes of travel, such as passengers walking or catching bus services to access train stations. Share taxis offer on-demand services in many parts of the world, which may compete with fixed public transport lines, or compliment them, by bringing passengers to interchanges. Paratransit is sometimes used in areas of low demand and for people who need a door-to-door service.Urban public transit differs distinctly among Asia, North America, and Europe. In Asia, profit-driven, privately-owned and publicly traded mass transit and real estate conglomerates predominantly operate public transit systems In North America, municipal transit authorities most commonly run mass transit operations. In Europe, both state-owned and private companies predominantly operate mass transit systems, Public transport services can be profit-driven by use of pay-by-the-distance fares or funded by government subsidies in which flat rate fares are charged to each passenger. Services can be fully profitable through high usership numbers and high farebox recovery ratios, or can be regulated and possibly subsidised from local or national tax revenue. Fully subsidised, free of charge services operate in some towns and cities.

For geographical, historical and economic reasons, differences exist internationally regarding use and extent of public transport. While countries in the Old World tend to have extensive and frequent systems serving their old and dense cities, many cities of the New World have more sprawl and much less comprehensive public transport. The International Association of Public Transport (UITP) is the international network for public transport authorities and operators, policy decision-makers, scientific institutes and the public transport supply and service industry. It has 3,400 members from 92 countries from all over the globe.

Rail transport

Rail transport is a means of transferring of passengers and goods on wheeled vehicles running on rails, also known as tracks. It is also commonly referred to as train transport. In contrast to road transport, where vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on ties (sleepers) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as slab track. This is where the rails are fastened to a concrete foundation resting on a prepared subsurface.

Rolling stock in a rail transport system generally encounters lower frictional resistance than rubber-tired road vehicles, so passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer facilities. Power is provided by locomotives which either draw electric power from a railway electrification system or produce their own power, usually by diesel engines. Most tracks are accompanied by a signalling system. Railways are a safe land transport system when compared to other forms of transport. Railway transport is capable of high levels of passenger and cargo utilization and energy efficiency, but is often less flexible and more capital-intensive than road transport, when lower traffic levels are considered.

The oldest known, man/animal-hauled railways date back to the 6th century BC in Corinth, Greece. Rail transport then commenced in mid 16th century in Germany in the form of horse-powered funiculars and wagonways. Modern rail transport commenced with the British development of the steam locomotives in the early 19th century. Thus the railway system in Great Britain is the oldest in the world. Built by George Stephenson and his son Robert's company Robert Stephenson and Company, the Locomotion No. 1 is the first steam locomotive to carry passengers on a public rail line, the Stockton and Darlington Railway in 1825. George Stephenson also built the first public inter-city railway line in the world to use only the steam locomotives all the time, the Liverpool and Manchester Railway which opened in 1830. With steam engines, one could construct mainline railways, which were a key component of the Industrial Revolution. Also, railways reduced the costs of shipping, and allowed for fewer lost goods, compared with water transport, which faced occasional sinking of ships. The change from canals to railways allowed for "national markets" in which prices varied very little from city to city. The spread of the railway network and the use of railway timetables, led to the standardisation of time (railway time) in Britain based on Greenwich Mean Time. Prior to this, major towns and cities varied their local time relative to GMT. The invention and development of the railway in the United Kingdom was one of the most important technological inventions of the 19th century. The world's first underground railway, the Metropolitan Railway (part of the London Underground), opened in 1863.

In the 1880s, electrified trains were introduced, leading to electrification of tramways and rapid transit systems. Starting during the 1940s, the non-electrified railways in most countries had their steam locomotives replaced by diesel-electric locomotives, with the process being almost complete by the 2000s. During the 1960s, electrified high-speed railway systems were introduced in Japan and later in some other countries. Many countries are in the process of replacing diesel locomotives with electric locomotives, mainly due to environmental concerns, a notable example being Switzerland, which has completely electrified its network. Other forms of guided ground transport outside the traditional railway definitions, such as monorail or maglev, have been tried but have seen limited use.

Following a decline after World War II due to competition from cars and airplanes, rail transport has had a revival in recent decades due to road congestion and rising fuel prices, as well as governments investing in rail as a means of reducing CO2 emissions in the context of concerns about global warming.

Rapid transit

Rapid transit or mass rapid transit (MRT), also known as heavy rail, metro, subway, tube, U-Bahn or underground, is a type of high-capacity public transport generally found in urban areas. Unlike buses or trams, rapid transit systems are electric railways that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles of any sort, and which is often grade separated in tunnels or on elevated railways.

Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on rail tracks, although some systems use guided rubber tires, magnetic levitation, or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to minimize gaps between train and platform. They are typically integrated with other public transport and often operated by the same public transport authorities. However, some rapid transit systems have at-grade intersections between a rapid transit line and a road or between two rapid transit lines. It is unchallenged in its ability to transport large numbers of people quickly over short distances with little to no use of land.The world's first rapid transit system was the partially underground Metropolitan Railway which opened as a conventional railway in 1863, and now forms part of the London Underground. In 1868, New York opened the elevated West Side and Yonkers Patent Railway, initially a cable-hauled line using static steam engines.

China has the largest number of rapid transit systems in the world at 31, with over 4,500 km of lines and is responsible for most of the world's rapid transit expansion in the past decade. The world's longest single-operator rapid transit system by route length is the Shanghai Metro. The world's largest single rapid transit service provider by number of stations (472 stations in total) is the New York City Subway. The busiest rapid transit systems in the world by annual ridership are the Tokyo subway system, the Seoul Metropolitan Subway, the Moscow Metro, the Beijing Subway, the Shanghai Metro, the Guangzhou Metro, the New York City Subway, the Mexico City Metro, the Paris Métro, and the Hong Kong MTR.

Royal Dutch Shell

Royal Dutch Shell plc (LSE: RDSA, RDSB), commonly known as Shell, is a British-Dutch oil and gas company headquartered in the Netherlands and incorporated in the United Kingdom. It is one of the six oil and gas "supermajors" and the fifth-largest company in the world measured by 2018 revenues (and the largest based in Europe). Shell was first in the 2013 Fortune Global 500 list of the world's largest companies; in that year its revenues were equivalent to 84% of the Dutch national $556 billion GDP. In the 2019 Forbes Global 2000, Shell was ranked as the ninth-largest company in the world (and the largest outside China and the United States), and the largest energy company.Shell is vertically integrated and is active in every area of the oil and gas industry, including exploration and production, refining, transport, distribution and marketing, petrochemicals, power generation and trading. It also has renewable energy activities, including in biofuels, wind, energy-kite systems, and hydrogen. Shell has operations in over 70 countries, produces around 3.7 million barrels of oil equivalent per day and has 44,000 service stations worldwide. As of 31 December 2014, Shell had total proved reserves of 13.7 billion barrels (2.18×109 m3) of oil equivalent. Shell Oil Company, its principal subsidiary in the United States, is one of its largest businesses. Shell holds 50% of Raízen, a joint venture with Cosan, which is the third-largest Brazil-based energy company by revenues and a major producer of ethanol.Shell was formed in 1907 through the amalgamation of the Royal Dutch Petroleum Company of the Netherlands and the "Shell" Transport and Trading Company of the United Kingdom. Until its unification in 2005 the firm operated as a dual-listed company, whereby the British and Dutch companies maintained their legal existence but operated as a single-unit partnership for business purposes. Shell first entered the chemicals industry in 1929. In 1970 Shell acquired the mining company Billiton, which it subsequently sold in 1994 and now forms part of BHP Billiton. In recent decades gas exploration and production has become an increasingly important part of Shell's business. Shell acquired BG Group in 2016, making it the world's largest producer of liquefied natural gas (LNG).Shell has a primary listing on the London Stock Exchange and is a constituent of the FTSE 100 Index. It had a market capitalisation of £185 billion at the close of trading on 30 December 2016, by far the largest of any company listed on the London Stock Exchange and among the highest of any company in the world. It has secondary listings on Euronext Amsterdam and the New York Stock Exchange. As of January 2013, Shell's largest shareholder was Capital Research Global Investors with 9.85% ahead of BlackRock in second with 6.89%.

Transport Layer Security

Transport Layer Security (TLS), and its now-deprecated predecessor, Secure Sockets Layer (SSL), are cryptographic protocols designed to provide communications security over a computer network. Several versions of the protocols find widespread use in applications such as web browsing, email, instant messaging, and voice over IP (VoIP). Websites can use TLS to secure all communications between their servers and web browsers.

The TLS protocol aims primarily to provide privacy and data integrity between two or more communicating computer applications. When secured by TLS, connections between a client (e.g., a web browser) and a server (e.g., should have one or more of the following properties:

The connection is private (or secure) because symmetric cryptography is used to encrypt the data transmitted. The keys for this symmetric encryption are generated uniquely for each connection and are based on a shared secret that was negotiated at the start of the session (see § TLS handshake). The server and client negotiate the details of which encryption algorithm and cryptographic keys to use before the first byte of data is transmitted (see § Algorithm below). The negotiation of a shared secret is both secure (the negotiated secret is unavailable to eavesdroppers and cannot be obtained, even by an attacker who places themselves in the middle of the connection) and reliable (no attacker can modify the communications during the negotiation without being detected).

The identity of the communicating parties can be authenticated using public-key cryptography. This authentication can be made optional, but is generally required for at least one of the parties (typically the server).

The connection is reliable because each message transmitted includes a message integrity check using a message authentication code to prevent undetected loss or alteration of the data during transmission.In addition to the properties above, careful configuration of TLS can provide additional privacy-related properties such as forward secrecy, ensuring that any future disclosure of encryption keys cannot be used to decrypt any TLS communications recorded in the past.TLS supports many different methods for exchanging keys, encrypting data, and authenticating message integrity (see § Algorithm below). As a result, secure configuration of TLS involves many configurable parameters, and not all choices provide all of the privacy-related properties described in the list above (see the § Key exchange (authentication), § Cipher security, and § Data integrity tables).

Attempts have been made to subvert aspects of the communications security that TLS seeks to provide, and the protocol has been revised several times to address these security threats (see § Security). Developers of web browsers have also revised their products to defend against potential security weaknesses after these were discovered (see TLS/SSL support history of web browsers).The TLS protocol comprises two layers: the TLS record and the TLS handshake protocols.

TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and the current version is TLS 1.3 defined in RFC 8446 (August 2018). TLS builds on the earlier SSL specifications (1994, 1995, 1996) developed by Netscape Communications

for adding the HTTPS protocol to their Navigator web browser.

Transport for London

Transport for London (TfL) is a local government body responsible for the transport system in Greater London, England. Its head office is 55 Broadway in the City of Westminster.TfL has responsibility for London's network of principal road routes, for various rail networks including the London Underground, London Overground, Docklands Light Railway and TfL Rail. It does not control National Rail services in London, however, but does for London's trams, buses and taxis, for cycling provision, and for river services. The underlying services are provided by a mixture of wholly owned subsidiary companies (principally London Underground), by private sector franchisees (the remaining rail services, trams and most buses) and by licensees (some buses, taxis and river services). TfL is also responsible, jointly with the national Department for Transport (DfT), for commissioning the construction of the new Crossrail line, and will be responsible for franchising its operation once completed.In 2015–16, TfL had a budget of £11.5 billion, 40% of which comes from fares. The rest comes from government funding (23%), borrowing (20%), Congestion Charge and other income (9%) and Crossrail funding (8%).

Transport in India

Transport system in India consists of transport by land, water and air. Public transport remains the primary mode of transport for most Indian citizens, and India's public transport systems are among the most heavily used in the world.Motor vehicle population in India is high as by international standards, with 24.85 million cars on the nation's roads as per 2013 records. In total, about 21 percent of households have two wheelers whereas only 4.7 percent of households in India have cars/jeeps/vans as per the 2011 Census. Despite this, the number of deaths caused by traffic is amongst the highest in the world and increasing. The automobile industry in India is currently rapidly growing with an annual production of over 4.6 million vehicles, with an annual growth rate of 10.5% and vehicle volume is expected to rise greatly in the future.India's rail network is the second-longest and the most heavily used system in the world, transporting 8.225 billion passengers and over 970 million tonnes of freight annually, as of 2015. The railways transport about 18 million citizens daily.

In 2015–16, Government of India, declared 106 National Waterways (NW) under Inland Waterways Authority of India to reduce the cost of transportation and lower the carbon footprint by moving the traffic from surface roads and railroads to waterways.Despite ongoing improvements in the transport sector, several aspects of transportation are still riddled with problems due to outdated infrastructure and lack of investment in less economically active parts of the country. The demand for transport infrastructure and services has been rising by around 10% a year with the current infrastructure being unable to meet these growing demands. According to Goldman Sachs, India will need to spend US$1.7 trillion on infrastructure projects over the next decade to increase economic growth.

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