Electric power transmission
Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines which facilitate this movement are known as a transmission network; this is distinct from the local wiring between high-voltage substations and customers, referred to as electric power distribution. The combined transmission and distribution network is known as the "power grid" in North America, or just "the grid". In the United Kingdom, Myanmar and New Zealand, the network is known as the "National Grid". A wide area synchronous grid known as an "interconnection" in North America, directly connects a large number of generators delivering AC power with the same relative frequency to a large number of consumers. For example, there are four major interconnections in North America. In Europe one large grid connects most of continental Europe. Transmission and distribution lines were owned by the same company, but starting in the 1990s, many countries have liberalized the regulation of the electricity market in ways that have led to the separation of the electricity transmission business from the distribution business.
Most transmission lines are high-voltage three-phase alternating current, although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current technology is used for greater efficiency over long distances. HVDC technology is used in submarine power cables, in the interchange of power between grids that are not mutually synchronized. HVDC links are used to stabilize large power distribution networks where sudden new loads, or blackouts, in one part of a network can result in synchronization problems and cascading failures. Electricity is transmitted at high voltages to reduce the energy loss which occurs in long-distance transmission. Power is transmitted through overhead power lines. Underground power transmission has a higher installation cost and greater operational limitations, but reduced maintenance costs. Underground transmission is sometimes used in environmentally sensitive locations. A lack of electrical energy storage facilities in transmission systems leads to a key limitation.
Electrical energy must be generated at the same rate. A sophisticated control system is required to ensure that the power generation closely matches the demand. If the demand for power exceeds supply, the imbalance can cause generation plant and transmission equipment to automatically disconnect or shut down to prevent damage. In the worst case, this may lead to a cascading series of a major regional blackout. Examples include the US Northeast blackouts of 1965, 1977, 2003, major blackouts in other US regions in 1996 and 2011. Electric transmission networks are interconnected into regional and continent wide networks to reduce the risk of such a failure by providing multiple redundant, alternative routes for power to flow should such shut downs occur. Transmission companies determine the maximum reliable capacity of each line to ensure that spare capacity is available in the event of a failure in another part of the network. High-voltage overhead conductors are not covered by insulation; the conductor material is nearly always an aluminum alloy, made into several strands and reinforced with steel strands.
Copper was sometimes used for overhead transmission, but aluminum is lighter, yields only marginally reduced performance and costs much less. Overhead conductors are a commodity supplied by several companies worldwide. Improved conductor material and shapes are used to allow increased capacity and modernize transmission circuits. Conductor sizes range from 12 mm2 with varying resistance and current-carrying capacity. For normal AC lines thicker wires would lead to a small increase in capacity due to the skin effect; because of this current limitation, multiple parallel cables are used when higher capacity is needed. Bundle conductors are used at high voltages to reduce energy loss caused by corona discharge. Today, transmission-level voltages are considered to be 110 kV and above. Lower voltages, such as 66 kV and 33 kV, are considered subtransmission voltages, but are used on long lines with light loads. Voltages less than 33 kV are used for distribution. Voltages above 765 kV are considered extra high voltage and require different designs compared to equipment used at lower voltages.
Since overhead transmission wires depend on air for insulation, the design of these lines requires minimum clearances to be observed to maintain safety. Adverse weather conditions, such as high wind and low temperatures, can lead to power outages. Wind speeds as low as 23 knots can permit conductors to encroach operating clearances, resulting in a flashover and loss of supply. Oscillatory motion of the physical line can be termed gallop or flutter depending on the frequency and amplitude of oscillation. Electric power can be transmitted by underground power cables instead of overhead power lines. Underground cables take up less right-of-way than overhead lines, have lower visibility, are less affected by bad weather. However, costs of insulated cable and excavation are much higher
Eminent domain, land acquisition, compulsory purchase, resumption/compulsory acquisition, or expropriation is the power of a state, provincial, or national government to take private property for public use. However, this power can be legislatively delegated by the state to municipalities, government subdivisions, or to private persons or corporations, when they are authorized by the legislature to exercise the functions of public character. In the Anglo-American historical context, property taken could be used only by the government taking the property in question; the most common uses of property taken by eminent domain have been for roads, government buildings and public utilities. However, in the mid-20th century, a new application of eminent domain was pioneered, in which the government could take the property and transfer it to a private third party; this was done only to a property, deemed "blighted" or a "development impediment", on the principle that such properties had a negative impact upon surrounding property owners, but was expanded to allow the taking of any private property when the new third-party owner could develop the property in such a way as to bring in increased tax revenues to the government.
Some jurisdictions require that the taker make an offer to purchase the subject property, before resorting to the use of eminent domain. However, once the property is taken and the judgment is final, the condemnor owns it in fee simple, may put it to uses other than those specified in the eminent domain action. Takings may be of the subject property in its entirety or in part, either quantitatively or qualitatively; the term "eminent domain" was taken from the legal treatise De jure belli ac pacis, written by the Dutch jurist Hugo Grotius in 1625, which used the term dominium eminens and described the power as follows:... The property of subjects is under the eminent domain of the state, so that the state or those who act for it may use and alienate and destroy such property, not only in the case of extreme necessity, in which private persons have a right over the property of others, but for ends of public utility, to which ends those who founded civil society must be supposed to have intended that private ends should give way.
But, when this is done, the state is bound to make good the loss to those. The exercise of eminent domain is not limited to real property. Condemnors may take personal property intangible property such as contract rights, trade secrets, copyrights; the taking of a professional sports team's franchise has been held by the California Supreme Court to be within the purview of the "public use" constitutional limitation, although that taking was not permitted because it was deemed to violate the interstate commerce clause of the U. S. Constitution. A taking of property must be accompanied by payment of "just compensation" to the owner. In theory, this is supposed to put the owner in the same position "pecuniarily" that he would have been in had his property not been taken, but in practice courts have limited compensation to the property's fair market value, considering its highest and best use. But though granted, this is not the exclusive measure of compensation. In most takings owners are not compensated for a variety of incidental losses caused by the taking of their property that, though incurred and demonstrable in other cases, are deemed by the courts to be noncompensable in eminent domain.
The same is true of appraisers fees. But as a matter of legislative grace rather than constitutional requirement some of these losses have been made compensable by state legislative enactments, in the U. S. may be covered by provisions of the federal Uniform Relocation Assistance Act. Most states use the term eminent domain, but some U. S. states use the term appropriation or expropriation as synonyms for the exercise of eminent domain powers. The term condemnation is used to describe the formal act of exercising this power to transfer title or some lesser interest in the subject property; the constitutionally required "just compensation" in partial takings is measured by fair market value of the part taken, plus severance damages. Where a partial taking provides economic benefits specific to the remainder, those must be deducted from severance damages; the former owners of the property receive full market value because some elements of value are deemed noncompensable in eminent domain law. The practice of condemnation came to the American colonies with the common law.
When it came time to draft the United States Constitution, differing views on eminent domain were voiced. The Fifth Amendment to the Constitution requires that the taking be for a "public use" and mandates payment of "just compensation" to the owner. In federal law, Congress can take private property directly by pa
Natural gas is a occurring hydrocarbon gas mixture consisting of methane, but including varying amounts of other higher alkanes, sometimes a small percentage of carbon dioxide, hydrogen sulfide, or helium. It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years; the energy that the plants obtained from the sun is stored in the form of chemical bonds in the gas. Natural gas is a occurring hydrocarbon used as a source of energy for heating and electricity generation, it is used as a fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Natural gas is called a non-renewable resource. Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is another fossil fuel found in close proximity to and with natural gas. Most natural gas was created over time by two mechanisms: thermogenic.
Biogenic gas is created by methanogenic organisms in marshes, bogs and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material. In petroleum production gas is burnt as flare gas; the World Bank estimates that over 150 cubic kilometers of natural gas are flared or vented annually. Before natural gas can be used as a fuel, but not all, must be processed to remove impurities, including water, to meet the specifications of marketable natural gas; the by-products of this processing include: ethane, butanes and higher molecular weight hydrocarbons, hydrogen sulfide, carbon dioxide, water vapor, sometimes helium and nitrogen. Natural gas is informally referred to as "gas" when compared to other energy sources such as oil or coal. However, it is not to be confused with gasoline in North America, where the term gasoline is shortened in colloquial usage to gas. Natural gas was discovered accidentally in ancient China, as it resulted from the drilling for brines.
Natural gas was first used by the Chinese in about 500 BCE. They discovered a way to transport gas seeping from the ground in crude pipelines of bamboo to where it was used to boil salt water to extract the salt, in the Ziliujing District of Sichuan; the discovery and identification of natural gas in the Americas happened in 1626. In 1821, William Hart dug the first natural gas well at Fredonia, New York, United States, which led to the formation of the Fredonia Gas Light Company; the state of Philadelphia created the first municipally owned natural gas distribution venture in 1836. By 2009, 66 000 km³ had been used out of the total 850 000 km³ of estimated remaining recoverable reserves of natural gas. Based on an estimated 2015 world consumption rate of about 3400 km³ of gas per year, the total estimated remaining economically recoverable reserves of natural gas would last 250 years at current consumption rates. An annual increase in usage of 2–3% could result in recoverable reserves lasting less as few as 80 to 100 years.
In the 19th century, natural gas was obtained as a by-product of producing oil, since the small, light gas carbon chains came out of solution as the extracted fluids underwent pressure reduction from the reservoir to the surface, similar to uncapping a soft drink bottle where the carbon dioxide effervesces. Unwanted natural gas was a disposal problem in the active oil fields. If there was not a market for natural gas near the wellhead it was prohibitively expensive to pipe to the end user. In the 19th century and early 20th century, unwanted gas was burned off at oil fields. Today, unwanted gas associated with oil extraction is returned to the reservoir with'injection' wells while awaiting a possible future market or to repressurize the formation, which can enhance extraction rates from other wells. In regions with a high natural gas demand, pipelines are constructed when it is economically feasible to transport gas from a wellsite to an end consumer. In addition to transporting gas via pipelines for use in power generation, other end uses for natural gas include export as liquefied natural gas or conversion of natural gas into other liquid products via gas to liquids technologies.
GTL technologies can convert natural gas into liquids products such as diesel or jet fuel. A variety of GTL technologies have been developed, including Fischer–Tropsch, methanol to gasoline and syngas to gasoline plus. F–T produces a synthetic crude that can be further refined into finished products, while MTG can produce synthetic gasoline from natural gas. STG+ can produce drop-in gasoline, jet fuel and aromatic chemicals directly from natural gas via a single-loop process. In 2011, Royal Dutch Shell's 140,000 barrels per day F–T plant went into operation in Qatar. Natural gas can be "associated", or "non-associated", is found in coal beds, it sometimes contains a significant amount of ethane, propane and pentane—heavier hydrocarbons removed for commercial use prior to the methane being sold as a consumer fuel or chemical plant feedstock. Non-hydrocarbons such as carbon dioxide, nitrogen and hydrogen sulfide must be removed before the natural gas can be transported. Natural gas extracted from oil wells is called casinghead gas (whether or not produced up the a
Traffic on roads consists of road users including pedestrians, ridden or herded animals, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel. Traffic laws are the laws which govern traffic and regulate vehicles, while rules of the road are both the laws and the informal rules that may have developed over time to facilitate the orderly and timely flow of traffic. Organized traffic has well-established priorities, right-of-way, traffic control at intersections. Traffic is formally organized in many jurisdictions, with marked lanes, intersections, traffic signals, or signs. Traffic is classified by type: heavy motor vehicle, other vehicle, pedestrian. Different classes may be segregated; some jurisdictions may have detailed and complex rules of the road while others rely more on drivers' common sense and willingness to cooperate. Organization produces a better combination of travel safety and efficiency. Events which disrupt the flow and may cause traffic to degenerate into a disorganized mess include road construction and debris in the roadway.
On busy freeways, a minor disruption may persist in a phenomenon known as traffic waves. A complete breakdown of organization may result in traffic gridlock. Simulations of organized traffic involve queuing theory, stochastic processes and equations of mathematical physics applied to traffic flow; the word traffic meant "trade" and comes from the Old Italian verb trafficare and noun traffico. The origin of the Italian words is unclear. Suggestions include Catalan trafegar "decant", an assumed Vulgar Latin verb transfricare'rub across', an assumed Vulgar Latin combination of trans- and facere'make or do', Arabic tafriq'distribution', Arabic taraffaqa, which can mean'seek profit'. Broadly, the term covers many kinds of traffic including network traffic, air traffic, marine traffic and rail traffic, but it is used narrowly to mean only road traffic. Rules of the road and driving etiquette are the general practices and procedures that road users are required to follow; these rules apply to all road users, though they are of special importance to motorists and cyclists.
These rules govern interactions with pedestrians. The basic traffic rules are defined by an international treaty under the authority of the United Nations, the 1968 Vienna Convention on Road Traffic. Not all countries are signatory to the convention and among signatories, local variations in practice may be found. There are unwritten local rules of the road, which are understood by local drivers; as a general rule, drivers are expected to avoid a collision with another vehicle and pedestrians, regardless of whether or not the applicable rules of the road allow them to be where they happen to be. In addition to the rules applicable by default, traffic signs and traffic lights must be obeyed, instructions may be given by a police officer, either or as road traffic control around a construction zone, accident, or other road disruption; these rules should be distinguished from the mechanical procedures required to operate one's vehicle. See driving. Traffic going in opposite directions should be separated in such a way that they do not block each other's way.
The most basic rule is. In many countries, the rules of the road are codified, setting out the legal requirements and punishments for breaking them. In the United Kingdom, the rules are set out in the Highway Code, which includes not only obligations but advice on how to drive sensibly and safely. In the United States, traffic laws are regulated by the states and municipalities through their respective traffic codes. Most of these are based at least in part on the Uniform Vehicle Code, but there are variations from state to state. In states such as Florida, traffic law and criminal law are separate, unless someone flees a scene of an accident, commits vehicular homicide or manslaughter, they are only guilty of a minor traffic offense. However, states such as South Carolina have criminalized their traffic law, so, for example, one is guilty of a misdemeanor for travelling 5 miles over the speed limit. Vehicles come into conflict with other vehicles and pedestrians because their intended courses of travel intersect, thus interfere with each other's routes.
The general principle that establishes who has the right to go first is called "right of way", or "priority". It establishes who has the right to use the conflicting part of the road and who has to wait until the other does so. Signs, signals and other features are used to make priority explicit; some signs, such as the stop sign, are nearly universal. When there are no signs or markings, different rules are observed depending on the location; these default priority rules differ between countries, may vary within countries. Trends toward uniformity are exemplified at an international level by the Vienna Convention on Road Signs and Signals, which prescribes standardized traffic control devices for establishing the right of way where necessary. Crosswalks are common in populated areas, may indicate that pedestrians have priority over vehicular traffic. In most modern cities, the traffic signal is used to establish the right of way on the busy roads, its primary purpose is to give each road a duration of time in which its traffic may use the intersection in an organized way.
Rights of way in England and Wales
In England and Wales, other than in the 12 Inner London Boroughs and the City of London, the "right of way" refers to paths on which the public have a protected right to pass and re-pass. The law in England and Wales differs from Scots law in that rights of way exist only where they are so designated, whereas in Scotland any route that meets certain conditions is defined as a right of way, in addition there is a general presumption of access to the countryside. Private rights of way or easements exist. Definitive maps of public rights of way have been compiled for all of England and Wales, as a result of the National Parks and Access to the Countryside Act 1949, except the 12 Inner London boroughs, along with the City of London, were not covered by the Act. Definitive maps exist for the Outer London boroughs. To protect the existing rights of way in London, the Ramblers launched their "Putting London on the Map" in 2010, with the aim of getting "the same legal protection for paths in the capital as exists for footpaths elsewhere in England and Wales.
Legislation allows the Inner London boroughs to choose to produce definitive maps if they wish, but none do so". The launch event of "Putting London on the Map" took place at the British Library, since the'Inner London Area' of the Ramblers has been working with Ramblers Central Office staff to try to persuade each of the Inner London boroughs of the desirability of producing definitive maps of rights of way". In 2011 Lambeth Council passed a resolution to work towards creating a definitive map for their borough, but this does not yet exist; the City of London has produced a Public Access Map. In England and Wales a public footpath is a path on which the public have a protected right to travel on foot and in some areas public footpaths form a dense network of short paths, it is probable. The majority of footpaths are shown on Ordnance Survey 1:50,000 maps. Local highways authorities are required to maintain the definitive map of all public rights of way in their areas and these can be inspected at council offices.
If a path is shown on the definitive map and no subsequent legal order exists the right of way is conclusive in law. Just because a path is not shown on that map does not mean that it is not a public path, as the rights may not have been recorded; the Countryside Agency estimated that over 10% of public paths were not yet listed on the definitive map. The Countryside and Rights of Way Act 2000 provides that paths that are not recorded on the definitive map by 2026 and that were in use prior to 1949 will automatically be deemed stopped up on 1 January 2026; the right of access on a public footpath only extends to walking, so there is no right to cycle or ride a horse on a public footpath. However, it is not a criminal offence to do so unless there is a traffic order or bylaw in place specifically: it is a civil wrong to ride a bicycle or a horse on a public footpath, action could be taken by the landowner for trespass or nuisance by the user; the highway right to use a right of way is restricted to passing and re-passing, associated activities, the taking of'usual accompaniments'.
Bedford Borough Council mentions that walkers may: take a pram, pushchair or wheelchair, where possible take a dog as long as on a lead or under close control admire the view, stop for a rest, have a small picnic on the verge take a short alternative route to get round an obstruction A public bridleway is a way over which the general public have the following, but no other rights: to travel on foot and to travel on horseback or leading a horse, with or without a right to drive animals of any description along the way. Note that although Section 30 of the Countryside Act 1968 permits the riding of bicycles on public bridleways, the act says that it "shall not create any obligation to facilitate the use of the bridleway by cyclists". Thus, the right to cycle exists though it may be difficult to exercise on occasion. Cyclists using a bridleway are obliged to give way to other users on horseback. Public bridleways are shown on Ordnance Survey 1:25,000 and 1:50,000 maps, but many public bridleways were recorded as footpaths only as a result of the burden of maintenance required by the National Parks and Access to the Countryside Act 1949 and so are now wrongly recorded on the definitive map.
Definitive Map Modification Orders are needed to correct these errors. A byway open to all traffic is a highway over which the general public have a right to travel for vehicular and all other kinds of traffic, but, used by the public as footpaths and bridleways are used, per Road Traffic Regulation Act 1984, section 15, as amended by Road Traffic Act 1991, Schedule 1. After the 2006 Regulations to the Countryside and Rights of Way Act 2000, BOATs should now more properly be referred to as byways. A road used as public path was one of the three types of public right of way introduced by the National Parks and Access to the Countryside Act 1949; the Countryside Act 1968 required all highway authorities to reclassify RUPPs in their area – as public footpaths but in practice as public bridleways unless public vehicular rights were demonstrated to exist in which case it
A rail trail is the conversion of a disused railway track into a multi-use path for walking and sometimes horse riding and snowmobiling. The characteristics of abandoned railways—flat, long running through historical areas—are appealing for various developments; the term sometimes covers trails running alongside working railways. Some shared trails are segregated, with the segregation achieved without separation. Many rail trails are long-distance trails. A rail trail may still include rails, such as light streetcar. By virtue of their characteristic shape, some shorter rail trails are known as greenways and linear parks; the only carrier to exist in Bermuda folded in 1948 and was converted to a rail trail in 1984. Some of the former right of way has been converted for automobile traffic, but 18 miles are reserved for pedestrian use and bicycles on paved portions; the rail bed spans the length of the island, connected Hamilton to St. George's and several villages, though several bridges are derelict, causing the trail to be fragmented.
The Kettle Valley Rail Trail in British Columbia uses a rail corridor, built for the now-abandoned Kettle Valley Railway. The trail was developed during the 1990s after the Canadian Pacific Railway abandoned train service; the longest rail trail in Canada is the Newfoundland T'Railway that covers a distance of 883 km ). Protected as a linear park under the provincial park system, the T'Railway consists of the railbed of the historic Newfoundland Railway as transferred from its most recent owner, Canadian National Railway, to the provincial government after rail service was abandoned on the island of Newfoundland in 1988; the rail corridor stretches from Channel-Port aux Basques in the west to St. John's in the east with branches to Stephenville, Bonavista and Carbonear. Following the abandonment of the Prince Edward Island Railway in 1989, the government of Prince Edward Island purchased the right-of-way to the entire railway system; the Confederation Trail was developed as a tip-to-tip walking/cycling gravel rail trail which doubles as a monitored and groomed snowmobile trail during the winter months, operated by the PEI Snowmobile Association.
In Quebec, Le P'tit Train du Nord runs 200 km from Saint-Jérôme to Mont-Laurier. In Toronto, there are the Beltline Trail and the West Toronto Railpath. In central Ontario, the former Victoria Railway line, which runs 89 kilometres from the town of Lindsay, north to the village of Haliburton, in Haliburton County, serves as a public recreation trail, it can be used for cross country skiing and snowmobiling in the winter months, walking and horse riding from spring to autumn. The majority of the rail trail passes through sparsely populated areas of the Canadian Shield, with historic trestle bridges crossing several rivers; the old Sarnia Bridge in St. Marys, was re-purposed as part of the Grand Trunk Trail; the former Grand Trunk Railway viaduct was purchased from Canadian National Railway in 1995. The Grand Trunk Trail was opened in 1998 with over 3 km of paved, accessible trail. In 2012, The re-purposing of the Sarnia Bridge was inducted into the North America Railway Hall of Fame. A railroad between Gateway Road and Raleigh Street in Winnipeg, was turned into a 7 km asphalt trail in 2007.
It is called the Northeast Pioneers Greenway, has plans for expansion into East St. Paul, to Birds Hill Park. A considerable part of the Trans Canada Trail are repurposed defunct rail lines donated to provincial governments by CP and CN rail rebuilt as walking trails; the main section runs along the southern areas of Canada connecting most of Canada's major cities and most populous areas. There is a long northern arm which runs through Alberta to Edmonton and up through northern British Columbia to Yukon; the trail is multi-use and depending on the section may allow hikers, horseback riders, cross country skiers and snowmobilers. In North America, the decades-long consolidation of the rail industry led to the closure of a number of uneconomical branch lines and redundant mainlines; some were maintained as short line railways. The first abandoned rail corridor in the United States converted into a recreational trail was the Elroy-Sparta State Trail in Wisconsin, which opened in 1967; the following year the Illinois Prairie Path opened.
The conversion of rails to trails hastened with the federal government passing legislation promoting the use of railbanking for abandoned railroad corridors in 1983, upheld by the U. S. Supreme Court in 1990; this process preserves rail corridors for possible future rail use with interim use as a trail. By the 1970s main lines were being sold or abandoned; this was true when regional rail lines merged and streamlined their operations. As both the supply of potential trails increased and awareness of the possibilities rose, state governments, conservation authorities, private organizations bought the rail corridors to create, expand or link green spaces; the longest developed rail trail is the 240 miles Katy Trail in Missouri. When complete, the Cowboy Trail in Nebraska will become the longest; the Beltline, in Atlanta, Georgia, is under construction. In 2030, its anticipated year of completion, it will be one of the longest continuous trails; the Atlanta BeltLine is a sustainable redevelopment project that will provide a network of public parks, multi-use trails and transit along a historic 22-mile railroad corridor circling downtown and connecting many neigh
Transport or transportation is the movement of humans 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 the Point B. Modes of transport include air, water, cable and space; the field can be divided into infrastructure and operations. Transport is important because it enables trade between people, essential for the development of civilizations. Transport infrastructure consists of the fixed installations, including roads, airways, waterways and pipelines and terminals such as airports, railway stations, bus stations, trucking terminals, refueling depots and seaports. Terminals may be used both for maintenance. Vehicles traveling on these networks may include automobiles, buses, trucks, watercraft and aircraft. Operations deal with the way the vehicles are operated, the procedures set for this purpose, including financing and policies. In the transport industry and ownership of infrastructure can be either public or private, depending on the country and mode.
Passenger transport may be public. 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 subsidized by governments, good planning of transport is essential to make traffic flow and restrain urban sprawl. Humans' first means of transport involved walking 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, 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, oxen or humans carrying goods over dirt tracks that 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 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 at the intersection of two bodies of water. Until the Industrial Revolution, transport remained slow and costly, production and consumption gravitated as close to each other as feasible; the Industrial Revolution in the 19th century saw a number of inventions fundamentally change transport.
With telegraphy, communication became independent of the transport of physical objects. The invention of the steam engine followed by its application in rail transport, made land transport independent of human or animal muscles. Both speed and capacity increased allowing specialization through manufacturing being located independently of natural resources; the 19th century 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, mechanical private transport originated; the first "modern" highways were constructed during the 19th century with macadam. Tarmac and concrete became the dominant paving materials. In 1903 the Wright brothers demonstrated the first successful controllable airplane, after World War I aircraft became a fast way to transport people and express goods over long distances. After World War II the automobile and airlines took higher shares of transport, reducing rail and water to freight and short-haul passenger services.
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. 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 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. Early in U. S. history, private joint-stock corporations owned most aqueducts, canals, railroads 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. However, a movement to privatize roads and other infrastructure has gained some ground and adherents.
A mode of transport is a solution that makes use of a particular type of vehicle and operation. The transport of a person or of cargo may invol