Transportation is the movement or conveying of persons and goods from one location to another. As human beings, from ancient times to the 20th century, sought to make their transport facilities more efficient, they have always endeavored to move people and property with the least expenditure of time, effort, and cost. Improved transportation has helped make possible progress toward better living, the modern systems of manufacturing and commerce, and the complex, interdependent urban economy present in much of the world today. This article will cover: (1) the history of transportation, with an emphasis on that in the United States; (2) the political, economic, and social effects of transportation; and (3) the future of transportation. The military aspects of transportation are covered in \Taircraft, military\t; \Larmored vehicle\ls; and \Tnaval vessels\t. EARLY HISTORY Land Transportation Primitive human beings soon supplemented their own carrying of goods and possessions by starting to domesticate animals--training them to bear small loads and pull crude sleds (see \Tanimal husbandry\t). The first animals so domesticated included asses, camels, dogs, elephants, goats, horses, and oxen. The invention of the \Twheel\t, probably in western Asia, was a great step forward in transport. As the wheel was perfected, crude carts and \Lwagon\ls began to appear in the Tigris-Euphrates valley about 3500 BC, and later in Crete, Egypt, and China. Wheeled vehicles could not use the narrow paths and trails used by pack animals, and early roads were soon being built by the Assyrians and the Persians. The Romans, however, were the major builders of roads (see \Troads and highways\t; \TRoman roads\t) in the ancient world, and at the peak of their power their well-constructed roads led from Rome to most parts of the expanding empire. Travelers could move at speeds of nearly 10 km/h (6 mph), a rate that was not materially bettered until the early 19th century. After the fall of Rome in the 5th century land haulage generally declined because the highways suffered from inadequate maintenance. Such improvements, however, as the horse collar (10th century), the addition of springs to coaches (mid-17th century; see \Tcoach and carriage\t), new methods of road construction, and the introduction of toll roads, or \Lturnpike\ls (18th century), all continued to ease and speed land travel. Water Transportation Water transportation also began early in human history. No doubt the first watercraft, the simple raft and the crude \Tcanoe\t, both evolved from floating logs. Along the Tigris and Euphrates rivers the first \Lboat\ls were either hide-covered wicker baskets or dugout canoes, and in Egypt bundles of papyrus rushes were built into crude watercraft. Later the Cretans and Phoenicians built wooden \Lship\ls--oar-propelled \Lgalley\ls with a single sail--that dominated trade on the Mediterranean. Water itself was moved via \Laqueduct\ls, possibly as early as the 10th century BC. The next major improvements in water transportation (see \Tshipbuilding\t) did not appear until late medieval times. The introduction of the compass (see \Tcompass, navigational\t) and \Trudder\t into Europe by 1300, and later the square sail, did much to improve ocean transportation. By the 15th century the nation-states of England, France, Portugal, and Spain were beginning to build three-masted ships, a vast improvement over earlier craft. Soon these countries were leaders in the Age of Exploration, which expanded ocean commerce well beyond the confines of the Mediterranean. Larger and more numerous sailing vessels improved commerce with the New World during the 17th and 18th centuries, and for a brief period in the 19th century U.S.-built clipper ships were actually faster than the early steamships. \Lcanal\ls were another important form of water transportation. The invention of the lock, which was in use in Europe before 1500, stimulated the construction of more and larger canals, such as the Canal du Midi in France, the extensive English canal system in the 18th century, and the U.S. network of the mid-19th century. MOTORIZED TRANSPORTATION The greatest improvements in transportation have appeared in the last two centuries, a period during which the \TIndustrial Revolution\t has vastly changed the economic life of the entire world. Steamships James Watt's \Tsteam engine\t, perfected in the 1760s, was to do much more than provide power for many factories in England. By the end of the 18th century, French, Scottish, and American inventors were trying to apply the steam engine to navigation. In 1775 a Frenchman, Jacques Perier, built an early \Tsteamboat\t, and in 1807, Robert \TFulton\t launched the steamboat \TClermont\t on the Hudson River. In 1819 the steamer \TSavannah\t crossed the Atlantic, and by the middle of the 19th century steam navigation was replacing the sailing vessel, with many of the new ships built of iron rather than wood. This new form of water transportation was particularly important in the broad Mississippi River valley of the United States. Hundreds of flat-hulled, tall-stacked western steamboats served the triangular territory reaching from Pittsburgh and Montana down to New Orleans. Until the 1850s the expansion of the western frontier was vitally tied to the side-wheelers and stern-wheelers serving the 25,700 km (16,000 mi) of navigable streams in the inland Mississippi River basin. The western steamboat gave way to the railroad only with the coming of the Civil War. Railroads Crude railways--horse-drawn wagons with wooden wheels and rails--had been used in English and European mines during the 17th century. Between 1797 and 1813, Richard \TTrevithick\t and other early inventors adapted primitive steam locomotives to the mine railway. In 1825, George \TStephenson\t built and equipped the 32-km (20-mi) Stockton and Darlington Railway, the first public railway in the world to be powered by a steam locomotive, and a fever of \Trailroad\t building began in England. Although it first appeared in England, the railroad had its most dramatic growth in the United States. By 1840 more than 4,800 km (3,000 mi) of railroad were already operating in the eastern states, a figure 40% greater than the total railroad mileage of Europe. By the eve of the Civil War the iron network in the United States was more than 48,000 km (30,000 mi) long, and the railroads of the western lines had nearly caught up with the ever-moving western frontier. By 1860 the railroad had clearly shown its superiority over turnpikes, canals, and steamboats. Following the Civil War several railroad lines were extended all the way to the Pacific coast (see \Ttranscontinental railroad\t), the first being the Union Pacific-Central Pacific, completed in 1869. Railroad construction in general was very rapid in the postwar decades; by 1890 the length of the U.S. rail system was 262,000 km (163,000 mi), and by 1916 it had reached an all-time high of 409,000 km (254,000 mi). Since World War I, however, the U.S. railroads have been in a decline, due partly to the rapid development of private automobiles, trucks, buses, pipelines, and airlines. Motor Vehicles The first new mode of transportation to challenge the railroad was the motor vehicle, which was made possible by the invention, in the 1860s and '70s, of the \Tinternal combustion engine\t. The \Tautomobile\t found its greatest popularity in the United States, where the first "horseless carriages" appeared in the 1890s. In 1908, Henry Ford introduced the \TModel T\t, which proved so popular that by 1914, Ford had adopted \Tmass production\t methods to meet the demand. The Federal Highway Act of 1921 provided for primary highway routes across the length and breadth of the nation. The typical American family purchased its first car during the 1920s, and by 1930 there were 23 million passenger cars registered in the United States. Two hundred million motor vehicles had been produced in the nation within 70 years of their first appearance. The automobile thus became in many ways as important to the 20th century as the railroads had been to the 19th. During the same period intercity \Lbus\les took over a large portion of commercial passenger travel, and trucks (see \Ttrucking industry\t) began carrying much of the nation's freight. Pipelines The first small pipelines (see \Tpipe and pipeline\t) in the United States appeared in the oil fields of Pennsylvania just after the Civil War, and by 1900, John D. Rockefeller controlled a network of about 64,000 km (40,000 mi). By 1980, pipelines were carrying 23% of the nation's intercity freight traffic. In most years since World War II pipelines have moved as much freight as highway trucks. Aviation At the turn of the century most people thought it preposterous that they would ever travel through the air in a machine heavier than the air itself. The airplane proved its potential in World War I, however, and in 1918 regular \Tairmail\t service was started between Washington, D.C., and New York City. Air passenger traffic expanded quickly in the 1930s, and by 1939 air travel accounted for 2% of all commercial intercity travel. Air travel grew rapidly after World War II and in 1957 exceeded rail passenger travel for the first time. In 1980 nearly 83% of all commercial travel in the United States was by air (see \Taircraft\t; \Taviation\t). POLITICAL, ECONOMIC, AND SOCIAL EFFECTS A nation's political development and success, both in peace and war, are rather directly tied to the transportation facilities available in that nation. Throughout history a nation's political unity and power to govern have varied with its success or failure in providing some measure of transportation. In the ancient world the broad Nile River made possible the centralized government as well as the prosperity of early Egypt. Several centuries later the power and wealth of the Roman Empire was in great measure due to its success in road building plus the wealth and variety of its waterborne Mediterranean trades. In the same way, the dominance of British sea power helped make possible the extent and wealth of the British Empire in the 18th and 19th centuries. In the 19th century the varied internal improvements, especially the railroad, also helped bring the distant western American frontier firmly under the political control of the United States. Transportation facilities have also had political significance as modern nations have provided their citizens with postal systems. Government Aid, Regulation, and Ownership Many governments in recent decades have provided aid for their transportation facilities, have regulated or placed legal restrictions upon their operation, and in many cases have taken full control through the process of nationalization. Both European nations and the United States aided the new modes of transport that appeared in the 19th and 20th centuries. Early in the 19th century the U.S. government gave modest land grants to some canal projects in the Northwest Territory and also subscribed to the stock of a few other canal companies. In the decades after 1850 many western railroads in the United States received federal land grants to help with their construction--grants that would finally reach a total of 53 million ha (131 million acres). In return the land-grant railroads gave special rates--often a reduction of 50%--for the shipment of the federal government's freight and troops. In the 20th century both federal and state governments have supplied much money, in addition to that collected from state and federal gasoline taxes, for highway construction. During the same period federal money has aided water transportation on the Great Lakes, the major rivers, and the coastal \Lwaterway\ls of the nation. Since World War I air transportation in the United States has received substantial federal grants for weather, navigational, and \Tairport\t facilities. \Tgovernment regulation\t of construction standards appeared in many nations in the early years of railroad development. As the railroad monopoly of transportation increased in the United States during the late 19th century, an insistent public demand for more government regulation developed. Federal legislation in 1887 established the \TInterstate Commerce Commission\t, which had some power to restrain freight rates. Much more stringent federal railroad regulation developed early in the 20th century during the Progressive movement. In the 1920s and '30s federal regulation over highway and air transportation was adopted. Most of the regulatory agencies concerned with transportation were transferred (1966) to the newly established Department of Transportation (see \TTransportation, U.S. Department of\t). In 1971 the creation of the federally subsidized \TAmtrak\t passenger service relieved most U.S. railroads of the annual passenger-service deficits they had known for many years. In 1976 the federal government set up the Consolidated Rail Corporation (Conrail) to take over the freight operations of the Penn Central and several other bankrupt lines in the northeastern United States. During 1979 and 1980 federal legislation generally reduced much of the governmental regulation of transportation in the United States. For centuries most highways and roads have been publicly owned or managed. In the past century other forms of transport have also been taken over by the government. By the middle decades of the 20th century nearly all the railroads outside of North America were government owned and operated. The rail system of the United States, which amounts to about one-fourth of the total world rail mileage, is one of the few in which private ownership and operation still prevails. In Canada rail operation and ownership is roughly half private and half nationalized. Most of the airlines and some of the ocean-shipping lines in Europe have also become government owned and operated. Economic Effects The economic impact of transportation has also been great. Many experts estimate that in modern industrial nations today the total costs of freight and travel (both commercial and private) amount to about one-fifth of the nation's gross national product. In the United States in the 1970s the \Tautomotive industry\t, directly or indirectly, was supporting one worker in seven among the gainfully employed. These relatively high costs of transportation have resulted in an interdependent economy that has greatly increased the standard of living for the industrialized world. In such an economy efficient transportation makes possible a greater division of labor, provides mass production with cheaper costs, and creates national and even worldwide markets. Today's developing countries, which have little industry and a low standard of living, rarely possess modern facilities of transportation. In the early 19th century a \TConestoga\t wagon on a poor road could economically carry only light, fairly high-value goods over short distances. In the modern United States the railroad freight car, the truck on a paved highway, the river barge, and the pipeline economically carry over long distances freight that is bulky, heavy, and relatively low in value. Corn from Iowa, wheat from Kansas, fruit and vegetables from Florida and California, coal from Wyoming, iron ore from Minnesota, automobiles from Detroit, furniture from North Carolina, and oil from Alaska all can be transported thousands of kilometers to distant markets. The same kind of change occurred in passenger travel between the time of the Concord \Tstagecoach\t and today's jet airliner. Travel that once took months now takes days or even hours. Travel from New York City to San Francisco in 1848 could take four months; in the 1920s a fast train made the trip in three days; and today a jet makes the trip in four or five hours. By the late 1970s the \TConcorde\t, a \Tsupersonic transport\t aircraft built by the British and French governments, was carrying passengers across the Atlantic Ocean at twice the speed of sound. Airline travel around the world has become so commonplace that the oceangoing passenger liners of the mid-20th century have almost disappeared. Social Effects The social effects of transportation have also been important. Improved transportation increases a people's mobility, which in turn allows a greater interchange of ideas and cultural accomplishments. More efficient transportation reduces isolation and makes educational and recreational facilities more available. Both the location and the growth of cities are dependent on transportation. Before the Industrial Revolution most large cities either were major seaports or were located on important navigable rivers. With the coming of railroads, towns that failed to obtain a railroad often became villages, whereas cities with a future were those which were becoming railroad terminals. In the mid-19th century, St. Louis, Mo., a river town, was soon surpassed in economic importance by Chicago, a growing rail terminal. In the last century the major industrial cities of the world have had their expanding populations served in turn by horsecars, electric streetcars, buses, \Lelevated railroad\ls, and \Lsubway\ls. Increased urban transportation, resulting from increased commercial traffic and increased commuter travel to and from cities, has caused such problems as increased congestion, air pollution, and damage to road surfaces; the pollutants from road surfaces are also major contaminants of the water systems (see \Tenvironmental health\t). The problems of urban transportation in the United States were relieved to some degree by the Urban Mass Transportation Act of 1964, which promoted the development of mass-transit facilities, such as rapid rail systems and better commuter bus and rail services, and encouraged a program of car pooling. The Highway Safety Acts of 1966 and 1970 and the Clean Air Amendment of 1970 are among several legislative attempts to decrease accidents, noise, and pollution and to facilitate travel on heavily used roads (see \Ttraffic control\t). The transport of hazardous materials--dangerous because of possible leakage en route--has also been increasingly regulated since 1970. In the 20th century the automobile created few new major cities but instead caused a major suburban expansion. Other social effects of the automobile--a decline in rural isolation, consolidation of rural schools, summer vacations by automobile, and new shopping centers--constituted a virtual revolution in American life. In 1956 the Interstate Highway Act provided federal aid for a system of four-lane superhighways (see \TInterstate Highway System\t) that vastly improved the nation's 4.8 million-km (3 million-mi) road network. THE FUTURE Although the emphasis on fuel conservation waned in the 1980s, few doubt that the issue will emerge again when oil scarcities loom, as they did in the 1970s. Future possibilities include automobiles with far greater fuel efficiency and improved mass-transit systems. Both will occur not only in response to oil-supply disruption, but also as an answer to increasing demands for cleaner air. Aviation experts anticipate the commercial development of hypersonic airplanes. The German Saenger will be both the first stage in a two-stage reusable space launcher and--in a modified version--a commercial passenger liner that will travel at speeds of Mach 4.4 and at altitudes of around 30,500 m (100,000 ft). The experimental Soviet spaceplane Tupelov Tu 155, and the U.S. National Aerospace Plane, scheduled to make its first flight in the mid-1990s, will both be powered by liquid hydrogen. \TJohn\t F. STOVER See also: \Tspace programs, national\t. Bibliography: Coyle, J. J., and Bardi, E. J., Transportation, 2d ed. (1986); Deold, A. R., et al., Transportation: The Technology of Moving People and Goods (1986); Hay, W. W., An Introduction to Transportation Engineering (1977; repr. 1987); Ransom, J., The Archaeology of the Transport Revolution (1984); Wood, D. F., and Johnson, J. C., Contemporary Transportation, 3d ed. (1989).