I.

Introduction

Transportation, movement of people and goods from one location to another. Throughout history, the economic wealth and military power of a people or a nation have been closely tied to efficient methods of transportation. Transportation provides access to natural resources and promotes trade, allowing a nation to accumulate wealth and power. Transportation also allows the movement of soldiers, equipment, and supplies so that a nation can wage war.

Transportation systems and the routes they use have greatly influenced both how and where people live. Reliable transportation allows a population to expand throughout a country’s territory and to live comfortably in remote areas far from factories and farms. The growth and expansion of the United States were directly related to the means of transportation available at the time. The more compact cities of the U.S. eastern seaboard are the result of early human- and animal-based transportation systems that allowed only short trips. The more sprawling cities of the western United States are the result of an automobile-based transportation system that permits much longer travel distances.

Transportation is vital to a nation’s economy. Reducing the costs of transporting natural resources to production sites and moving finished goods to markets is one of the key factors in economic competition. The transportation industry is the largest industry in the world. It includes the manufacture and distribution of vehicles, the production and distribution of fuel, and the provision of transportation services. In 2000, approximately 3.2 percent of the U.S. gross domestic product and an estimated 7.4 percent of all jobs in the United States were related to the transportation industry.

The same transportation systems that link a nation can also be used in the nation’s war efforts. The rapid movement of troops, equipment, and supplies can be a deciding factor in winning a battle or a war. Just as mobilizing a nation’s military strength is critical to success, disabling an enemy’s transportation system is usually an early strategic objective of any armed conflict.

In the later 20th century, people became more aware of how transportation systems affect the environment. For example, the burning of petroleum-based fuels for motor vehicles creates pollution that can be harmful to human health. In the United States, the Environmental Protection Agency (EPA) estimates that three-quarters of all carbon monoxide and one-half of all oxides of nitrogen come from motor vehicles. In addition, petroleum-based transportation is responsible for approximately one-third of carbon dioxide emissions in the United States, an important contributor to global warming. Transportation accounts for 66 percent of total U.S. oil consumption. Other environmental effects of transportation systems include impacts on noise levels, water quality, hazardous materials, natural habitats, and wetlands. Many governments now require that before a new transportation project is begun a detailed study called an environmental impact statement must be prepared to anticipate how the project will affect the environment.

II.

Methods of Transportation

Transportation is usually classified by the medium in which the movement occurs, such as by land, air, water, or pipeline. Within each of the first three media, many different methods are used to move people and goods from place to place. Pipelines are used mainly to transport liquids or gases over long distances.

A.

Land Transportation

Land transportation is the dominant form of transportation in the world. People can move about land under their own power, either by walking or by other forms of human-powered transportation such as the bicycle. People also use domestic animals as a means of transportation, both for riding and for pulling wheeled wagons or carts. The most common forms of land transportation combine the wheel with electric or fuel-powered engines to move people and freight quickly and efficiently.

A.1.

Human Power

Human-powered transportation, such as walking or bicycling, relies entirely on human muscle power for movement. The earliest footpaths were likely based on animal migration routes, and ancient cultures developed extensive paths and roads for both transportation and communication. The ancient Greeks and the Inca Empire of South America were just two of the cultures that employed runners to carry messages in relays over many kilometers. The Incas constructed over 16,000 km (10,000 mi) of roads in South America in the 15th century and were able to relay a message 400 km (250 mi) in one day. Today, in many countries of the world, human-powered transportation remains the main form of transportation. In African cities, two-thirds of daily trips are made by walking. Even in automobile-dominated North American and European cities, walking is an important mode of transportation.

Special equipment, such as skis and snowshoes, has long been used to help people move over difficult terrain, such as snow-covered ground. Other inventions, such as the bicycle, make travel over flat terrain faster and more efficient. The Rover safety bicycle, one of the first practical bicycle designs, was invented around 1885 in Great Britain. Today, in Beijing, China, residents own over 8 million bicycles. In cities in Denmark, between 20 and 30 percent of daily trips are made on bicycles. In many Asian cities, bicycle-like vehicles called rickshaws carry between 10 and 20 percent of the freight moved daily. In Africa, the bicycle is the most common means of traveling intermediate distances.

A.2.

Domestic Animals

People have used domestic animals for thousands of years to help transport goods over longer distances. Pack-animal caravans using domesticated donkeys originated as early as 3500 bc. Pack animals are still used today in many parts of the world, particularly in rugged or hilly terrain where motor vehicles cannot travel. Other pack animals include llamas, camels, mules, oxen, water buffalo, dogs, goats, elephants, reindeer, and horses. The horse, with its superior speed and range, has been a favorite animal for transportation use.

A.3.

The Wheel

The origin of the wheel is unknown, but once it was invented, knowledge of the wheel spread rapidly throughout the Mediterranean and Asian world. Wheeled vehicles made the movement of goods much easier. The earliest known examples of wheels are from Mesopotamia and date from about 3500 to 3000 bc. The cart or wagon, pulled by humans or animals, was the first wheeled vehicle. Today, animal-drawn carts are still used in many countries, primarily to move freight but sometimes to transport people. The horse-drawn chariot, a faster version of the cart, became an important instrument of warfare because it could overpower enemy soldiers quickly. The chariot appeared in Mesopotamia around 2000 bc, and its use later spread to Egypt, Persia, Greece, Rome, and other ancient civilizations.

While the invention of the wheel was important to the development of transportation in Europe and Asia, the wheel was unknown to the ancient civilizations of North and South America. People in these areas used pack animals or dragged goods on crude sledges. Europeans brought the wheel to the New World as they began to settle there in the 16th century.

Horse-drawn stagecoaches and covered wagons played a critical role in the development of the United States and Canada in the 1800s. Conestoga wagons, covered wagons that could carry loads weighing up to 7 tons, were used extensively in the settlement of the western United States. See also Coach (vehicle).

A.4.

Railroads

Railroads are paths of parallel metal rails that allow a wheeled vehicle to move more easily by reducing friction. Iron rails were first used in the early 1800s to guide horse-drawn wagons. After the invention of the steam locomotive in 1804, steam engines replaced horses as the primary means of power. Modern locomotives commonly use electric motors or diesel engines and pull long trains of passenger or freight cars.

The benefits of rail transportation in both speed and carrying capacity made it superior to other methods of transportation in the 1800s. In the United States and Canada, with their vast expanses of territory, the railroad became a major means of cross-country transportation. In many countries, rail continues to be the main mode of passenger travel. In Europe and Japan, major cities are connected by high-speed passenger trains, such as the French TGV (Train à Grande Vitesse) and the Japanese Shinkansen trains, popularly known as bullet trains. The Shinkansen train can reach speeds of 300 km/h (186 mph).

Railroads have had a profound impact on civilization. Most importantly, the efficiency and speed of rail travel allow a nation’s population, industry, and agriculture to be established throughout that nation’s territory, even in previously remote areas. Rail transportation has also played a significant role in urban transportation systems (see Public Transportation).

A.5.

Motor Vehicles

Motor vehicles make up a broad class of self-propelled land-transportation devices that generally use internal-combustion engines and gasoline or diesel fuel for power. Most motor vehicles are designed to travel on roads, but specialized vehicles with sturdier construction are used for off-road travel over irregular terrain. Motor vehicles range from motorcycles and automobiles for personal use to trucks, which can transport large amounts of cargo, and buses, which can carry many passengers.

The first self-propelled vehicle was powered by steam. French engineer Nicholas-Joseph Cugnot built a steam-propelled vehicle in 1769. Between 1860 and 1890, innovations in steam-engine technology led to more steam-powered vehicles, primarily in France. At the beginning of the 20th century, gasoline-powered automobiles began to emerge as the dominant form of motor vehicle. Automobiles and other motor vehicles grew especially popular in the United States. From a relatively modest number in 1900, the number of motor vehicles in the United States reached 458,500 by 1910 and 6.2 million by 1918. At the end of the 20th century, over 130 million automobiles, 69 million light trucks, and 1.2 million heavy trucks were in use in the United States, being driven an estimated 4.5 trillion km (2.8 trillion mi) per year.

The heavy truck, which first came into mass production just prior to World War I (1914-1918), has become a major means of moving freight. It is a major competitor with railroads for freight business. The bus was developed in response to the apparent popularity of riding in motor vehicles. In many nations buses are a major form of urban and intercity passenger transportation.

The motorcycle is one of the most prolific forms of individual urban transportation in the world today. The growth of motorcycle or motorbike use has been especially large in Asian cities, where motorcycles provide a means of bypassing congested automobile traffic.

One of the few motor vehicles that does not use wheels is the snowmobile, which uses a drive track (made of a belt of rubber) and a pair of skis to move through snow. Although used for basic transportation in areas with heavy winter snows, the snowmobile is mostly used as a recreational vehicle. Over 200,000 snowmobiles are sold annually in the United States, Canada, and Europe.

B.

Air Transportation

Air travel has revolutionized global transportation by dramatically reducing the time needed to travel great distances. Journeys across nations or oceans that might have taken weeks or months can now be made in a matter of hours. With large numbers of people traveling in airplanes, air transportation has become a major part of the world’s transportation system. See also Aviation.

B.1.

Airplanes

Airplanes are heavier-than-air craft that use wings to produce lift in order to fly. Airplanes transport people from place to place and also ferry shipments of mail, perishable goods, and other important cargo (see Air Transport Industry). The airplane has also revolutionized warfare. Many aeronautical advances in technology, such as the jet engine, were achieved by military engineers and designers (see Air Warfare; Military Aircraft).

The first sustained, piloted flight of an airplane was made in 1903 by American brothers Orville and Wilbur Wright at Kitty Hawk, North Carolina. In 1914 the first commercial air service began in Florida. Commercial flights began to be flown throughout the United States, Europe, and the rest of the world. As technology improved, longer flights became possible. American aviator Charles Lindbergh’s solo crossing of the Atlantic Ocean in 1927 helped spark public interest in air travel between continents.

Advances in technology produced faster, larger, and more durable airplanes. The introduction of the turbojet engine in 1941 helped inaugurate the jet age in world travel in the years after World War II (1939-1945). The first commercial jet flight in the United States, made by a Boeing 707, occurred in 1958. To handle ever-increasing passenger demand, jet aircraft were made bigger and faster. The Boeing 747 jumbo jet, which can carry over 300 passengers, entered service in 1970. The supersonic British-French Concorde began regular passenger service in 1976, but the aircraft did not prove commercially viable and went out of service in 2003.

In the 1980s McDonnell Douglas introduced the twin-engine MD-80 family of jets, and Boeing came out with the narrow-body 757 and wide-body 767 twin jets. Airbus, a European consortium and one of the largest airplane manufacturers in the world, had developed the A300 wide-body twin during the 1970s. During the 1980s and 1990s Airbus expanded its family of aircraft, introducing the larger A330 twin and the A340, a four-engine airplane for longer routes, on which passenger loads are somewhat lighter. In 2000 the company launched production of the A380, a superjumbo jet that will seat 555 passengers on two decks, both of which extend the entire length of the fuselage. Scheduled to enter service in 2006, the jet will be the world’s largest passenger airliner.

B.2.

Helicopters

A helicopter obtains lift from a set of rotor blades rather than from fixed wings, as does an airplane. Helicopters are sometimes used in cities to carry travelers from suburban or downtown locations to airports. Helicopters are also used to provide medical evacuation, traffic reporting, and access to difficult-to-reach spots, such as ocean oil platforms and mountainous regions. Helicopters are also important military vehicles. Military forces use them for cargo transport, for medical evacuation, and as gunships.

The first successful helicopter liftoff occurred in 1907, when a French helicopter left the ground for a few seconds. However, more refinements were needed before helicopters became practical. Germany produced the first practical helicopter in 1936, and the United States Army unveiled its wartime helicopter in 1942. Helicopters were first used for military purposes during World War II.

B.3.

Lighter-Than-Air Vehicles

Balloons and airships are lighter-than-air vehicles that rely on hot air or on lighter-than-air gases such as helium or hydrogen for lift. Balloons rely on wind currents for propulsion and are used mostly for recreation or high-altitude weather research. Airships, such as blimps and dirigibles, combine a lighter-than-air gas bag with propellers for navigation and maneuvering.

Airships were once used for passenger traffic and showed much promise as a means of transportation. However, their popularity declined in response to several major accidents, including the disaster that befell the German airship Hindenburg in New Jersey in 1937. Today, small blimps using helium are popular for advertising purposes. They may often be seen at major sporting events.

B.4.

Recreational Air Vehicles

Other types of air vehicles, which are used primarily for recreational purposes, exist as well. Gliders are simple airplanes without motors that fly on wind currents. Ultralights are lightweight, motorized flying machines that fly at slow speeds and low altitudes.

C.

Water Transportation

Some of the greatest achievements in transportation relate to methods of crossing water. Two-thirds of Earth’s surface is covered by water, so the progress of civilization is naturally tied to the ability to move over water. Water transportation has progressed from early rafts and canoes to more-complex sailing ships to today’s large passenger and freight ships. See also Ship.

C.1.

Rafts and Canoes

Rafts and canoes are the simplest means of travel on water. A raft is a simple floating structure, usually made by tying together floating material, such as logs or papyrus stalks, to provide buoyancy. Rafts have been used since the earliest recorded times. In some cases, animal skins were used to cover a wooden frame or airtight animal bladders were fastened to wooden planks. Similar designs can be found from early India and Ireland. Some ancient designs are still used in remote areas of Tibet and in parts of Africa and South America.

C.2.

Oar-Driven Boats

Rafts and canoes are ordinarily propelled with poles or paddles, but as boats became larger, a more powerful form of propulsion was necessary. By 3000 bc the Egyptians had replaced paddles with oars, which are essentially long paddles fastened to the side of a boat so they can pivot. Oars allow the user to push, or row, against the water, thereby increasing power and speed. The Phoenicians, the Greeks, and the Romans developed oar-driven trading vessels and warships known as galleys. For propulsion a galley often used a sail in addition to banks of oars protruding from the side of the ship. The speed and maneuverability of galleys made them a dominant force in Mediterranean sea transportation in ancient times.

Another example of a rowed boat was the long boat of Scandinavia. These boats were approximately 20 m (70 ft) in length and initially relied on rowing for propulsion. With such boats, the Norsemen explored vast areas of northern Europe. With the addition of sails, they reached Iceland and Greenland by ad 800.

C.3.

Sailing Vessels

Sailing ships and sailboats use the power of the wind pushing against large sails for propulsion. By harnessing the power of the wind, early oceangoers were able to travel greater distances than they could have by sheer muscle power alone. Sailing ships were popular for transporting people, cargo, and soldiers until the introduction of steam-powered vessels in the 1800s. Today small sailboats and yachts are used primarily for recreation and sport.

Early Egyptian drawings show tree branches being used as sails, but by 3000 bc the branches had been replaced by rectangular sails made of papyrus hung crosswise from a mast. Later, cloth fabric was used for sails. Many of the early sea travels of the Phoenicians, the Greeks, and the Romans took place in galleys equipped with sails.

As sailing ships became larger and more durable, longer trips of discovery were made. Ancient trade expeditions from the Arabian peninsula to India left in the spring to catch easterly seasonal winds and returned in the fall with westerly winds. These westerly winds also allowed Chinese explorers to travel to India and Africa. In the late 1400s and early 1500s, European explorers discovered westerly winds that allowed travel to the newly discovered territory in the Western Hemisphere and easterly winds that allowed the return voyage to Europe. Christopher Columbus reached the New World in 1492. In 1521 Ferdinand Magellan became the first to circumnavigate the world in a sailing ship.

The Dutch and British developed large vessels for the transport of tea and spices from China and the East Indies (now Indonesia). In 1818 the first regularly scheduled transatlantic ship service was inaugurated between New York and London. The clipper ship was developed in the early 1800s to provide transportation for goods that had to be transported quickly, such as perishable items. However, the clipper ship, with a long and narrow hull, sacrificed cargo space to gain speed. Sailing ships eventually declined in use as reliable oceangoing steamships went into service.

C.4.

Canal Vessels and Riverboats

A canal is an artificial waterway that can be used to transport people and goods. Boats that travel on canals and rivers usually have a shallow draft, or depth, so they can navigate shallow waters. One type of shallow boat frequently used on canals and rivers is the barge. Barges are essentially large floating containers. Barges have no means of propulsion, so they require another boat to push or pull them. Boats traveling along a canal or river can also be pulled from shore, either by humans or by animals such as oxen, water buffalo, and mules.

Canals have been used for centuries for transportation. The ancient Assyrians and Egyptians built them. In China, the 1,900-km- (1,200-mi-) long Grand Canal was constructed over a long period of time, largely in the 7th and 13th centuries. In North America, Tenochtitlán, the capital of the Aztec Empire, relied almost exclusively on canals for transportation.

Canals built in Europe in the 18th century were used to transport coal from mines to steam-powered mills and to transport finished goods to market cities and ports. The Dutch, the French, and the British all constructed extensive canal systems by the mid-18th century. The canal-building era in the United States began in 1825 with the completion of the Erie Canal, connecting the Hudson River in New York with Lake Erie. Between 1825 and 1840 over 4,800 km (3,000 mi) of canals were constructed in the United States. However, by 1850, canals faced increased competition from railroads as an efficient means to transport goods.

Ship canals are much deeper than the canals ordinarily used by barges and river traffic. Ship canals provide oceangoing ships with direct access to inland ports and to other waterways. Ship canals have had a significant impact on world transportation. The best examples of such canals are the Suez Canal and the Panama Canal. The Suez Canal in Egypt is 195 km (121 mi) long and connects the Mediterranean Sea with the Gulf of Suez, part of the Red Sea. It opened to traffic in 1869. The Panama Canal in Panama, in Central America, measures 81.63 km (50.72 mi) in length and connects the Atlantic and Pacific Oceans. The Panama Canal was completed in 1914. In both cases, the canal shortened the trip between bodies of water by more than half the time previously needed. One of the most important inland waterway systems in North America is the Saint Lawrence River with its connection to the Great Lakes through the Saint Lawrence Seaway. Using its canals, locks, and navigable river channels, ships can travel from the Atlantic Ocean to Chicago, Illinois, and other industrial cities of the Great Lakes region, a distance of almost 3,900 km (2,400 mi).

Rivers also provide important transportation routes, and many early cities were located on rivers to take advantage of the natural waterways. The application of the steam engine to riverboats in the early 1800s revolutionized transportation on rivers. In 1807 American inventor Robert Fulton’s double-paddle-wheeled steamboat Clermont began service on the Hudson River in New York between Albany and New York City. The Clermont helped demonstrate the commercial practicality of steamboat operation in the United States. By the mid-1850s, steamboats driven by large paddle wheels were the major means of carrying passengers on the Mississippi River. The end of the U.S. riverboat era occurred just after the Civil War (1861-1865), when rail transportation proved to be more appealing. Barges are still used on many rivers, including the Mississippi, for transporting freight.

C.5.

Steamships

Oceangoing steamships, constructed with strong iron hulls, greatly reduced the time needed to travel across oceans. The Savannah in 1819 was the first ship equipped with a steam engine to cross the Atlantic Ocean. By 1838 several steam-powered paddle wheelers were crossing the Atlantic, and in 1840 the first regularly scheduled steamship service began. Steamships of the day featured several innovations that made them more competitive and reliable. Screw-type propellers (rather than paddle wheels), high-pressure boilers, and better steam turbines helped increase ship speeds. As a result, steamships became the dominant form of ocean travel in the late 1800s. Such ships were largely replaced by gas-turbine and diesel-powered vessels in the early 1900s.

C.6.

Modern Passenger Liners

The most recent type of oceangoing passenger liner is the cruise ship, a specially designed vessel providing luxurious surroundings and entertainment to passengers as the ship takes a short cruise. Cruise ships are usually around 270 m (900 ft) long and carry approximately 2,000 passengers. They generally cruise the Caribbean Sea, the Mediterranean Sea, the Alaska coast, or the South Pacific.

Cruise ships had their beginning in the mid-1800s, as shipping lines began to operate passenger ships that catered to wealthy patrons traveling between the United States and Europe. The golden age of luxury passenger liners occurred between 1900 and 1940, when British, German, French, and American companies vied to provide the most luxurious and fastest trip between Europe and the United States.

World War II interrupted passenger-liner traffic, but passenger liners continued to enjoy a brief period of popularity after the war. New ships were built, the most notable being the American United States in 1952 and the British Queen Elizabeth 2, which was launched in 1967. However, beginning in the 1960s, the passenger-liner market was rapidly captured by transatlantic airplane flights, and the luxury passenger liners were soon removed from service, except for a few that remained as tourist attractions.

C.7.

Cargo Vessels

Cargo vessels are special oceangoing ships that are designed exclusively for carrying large amounts of cargo. Different vessels are designed for carrying different kinds of cargo, such as liquids, bulk cargo (for example, grain or ore), or containers of preloaded materials. See also Shipping Industry.

The container ship transports large metal containers that have been preloaded with cargo. Containers are convenient and easy to load onto a ship, and they effectively use the space in a ship’s cargo hold. The containers measure 2.4 m × 2.4 m × 6 m (8 ft × 8 ft × 20 ft) in size and can be loaded at the manufacturing site. Containers are transported to and from the dock by rail, truck, or barge. Large overhead cranes pick up the containers and load them onto the ship. The ship travels to its destination port, where the containers are unloaded and then delivered to their individual destinations. Container vessels can load and unload quickly and provide shipping companies with a fast and secure means of moving general cargo. Some container ships can carry over 6,800 containers.

Some ships have been designed to handle containers that are on wheeled chassis. These ships are called roll-on/roll-off vessels because of their means of moving containers onto and off of the vessel. Lighter-aboard-ship (LASH) vessels are based on a similar concept. LASH vessels transport detachable barges that are floated from shore to the ship. This is useful in places where shallow water might prevent a conventional ship from docking or in ports that cannot accommodate large ships.

The bulk carrier is a special vessel designed to carry large quantities of loose material, such as ore or grain. Bulk carriers are common not only on the ocean but also for transport on the Great Lakes in North America. For example, 90 percent of the annual tonnage through the Saint Lawrence Seaway is bulk cargo.

Tankers are specially designed vessels with cargo spaces that hold liquid materials. With the increasing reliance on petroleum as a source of energy, supertankers have grown to more than 500,000 tons in displacement. Such ships are so large that they cannot fit through the Suez and Panama Canals, and thus they must go around the tip of Africa or South America. Because of this restriction, many of the world’s tankers displace no more than 200,000 tons, the maximum vessel size permitted in the Suez Canal. Other vessels have been designed to carry petrochemical products and liquefied natural gas.

C.8.

Military Vessels

Boats and ships have been used in warfare since the earliest times. The most important development in the evolution of the modern warship occurred in 1859, when the French launched the Gloire, the first iron-plated ship. The first battle between two iron-plated ships occurred in the American Civil War, when the Union ironclad Monitor fought the Confederate ironclad Virginia to a standstill (see Monitor v. Virginia). During World War II the specialization in warships reached its peak. The navies that fought in World War II used specialized ships such as battleships, aircraft carriers, cruisers, destroyers, destroyer escorts (frigates), minesweepers, torpedo boats, and landing craft, in addition to numerous support vessels. The aircraft carrier, a floating airfield that can carry about 85 aircraft, and the nuclear-powered submarine, which can travel underwater for months at a time, have had the biggest impact on naval warfare. See also Naval Vessels.

C.9.

Hydrofoils and Hovercraft

Hydrofoils and hovercraft are specialized water vehicles. A hydrofoil has small wing-like surfaces, called foils, that are attached to the bottom of its hull. As the hydrofoil accelerates, the foils act much like small aircraft wings, lifting most of the hull out of the water. Because less of the hull is in the water, less effort is used to push the hull against the resistance of the water. Hydrofoil speed varies, but most passenger-carrying hydrofoils can travel about 100 km/hr (about 60 mph). Some experimental models can travel even faster.

The hovercraft is a type of vehicle that is lifted entirely off the water surface by a cushion of air. Hovercraft can be propelled by giant air propellers or by water jets. Such vessels are not limited to moving over water but can also move over land. Because the vessel does not contact the surface, relatively high speeds can be obtained. Hovercraft have been used for search and rescue, for moving freight, and for passenger transportation. See also Air-Cushion Vehicle.

C.10.

Ferries

Ferries are used to transport people, animals, and vehicles over water in places where bridges would be inconvenient or otherwise impossible to build. Modern ferries provide commuter service in port cities such as Seattle, Washington. Ferries also provide interisland transportation in such locations as Hawaii, the Philippines, and the Mediterranean. High-speed ferries transport vehicles and passengers between specific points, such as between British and French ports on the English Channel. Rail-car ferries are used in Scandinavia. In the United States today, the largest ferryboat system is operated in Puget Sound near Seattle, Washington, where 29 ferries carry 26 million passengers yearly. The largest ferryboat in this system can carry 2,500 passengers and over 215 automobiles.

C.11.

Motorboats and Personal Craft

Smaller motorboats have been used for many years for recreational purposes. Such boats have either outboard motors, which are attached to the outside of the boat, or inboard motors, which are located within the hull itself. In 1999 there were about 17 million recreational boats in the United States.

C.12.

Pipelines

Pipelines are a unique form of transportation used to move liquids, gases, or solid/liquid mixtures over great distances. Pipelines consist of two major components: pipes and pumping stations. A piston in a pump forces liquid out of the pump and into the pipe. A vacuum created by the departing liquid forces more liquid to enter the pump, and that liquid in turn is forced out as the liquid before it was. With pumping stations placed appropriately along a pipeline, liquid can be moved great distances.

Pipelines are commonly used to transport crude oil (see Petroleum). Oil pipelines have been constructed in all parts of the world, primarily in oil-producing regions such as the Middle East, the North Sea, southern Russia, the South China Sea, Texas, Oklahoma, and Alaska. In 1999 there were approximately 248,000 km (154,000 mi) of pipelines for crude oil or petroleum products. Also in 1996, the latest year for which figures are available, there were 2,054,029 km (1,276,315 mi) of pipelines for natural gas in the United States. Pipelines are also used to transport solids suspended in liquids, such as coal slurry, which consists of powdered coal suspended in water.

III.

Transportation Service Providers

The many companies and government agencies that provide transportation to the public and to businesses are known as service providers. They are classified into two major groups: freight and passenger. Freight service providers transport cargo, such as manufactured products, raw materials, and food, and are generally hired by businesses. Passenger service providers move people from place to place and are usually hired by individuals. Both freight and passenger service providers often operate out of a facility known as a terminal. Terminals are centralized meeting points where service providers can manage the flow of transportation vehicles, serve customers, and efficiently load and unload freight and passengers.

A.

Freight Service

Freight transportation companies specialize in moving large amounts of cargo quickly and efficiently. Some companies use their own fleets of vehicles to transport their goods, whereas other companies hire service providers to ship their goods.

The for-hire service providers are owned by individuals, partnerships, or corporations as part of the private sector of the economy, particularly in the United States. In many other countries, the government holds partial or total ownership of the for-hire transportation industry.

Service providers compete with one another for freight business on the basis of such standards as the cost of shipment, delivery time, frequency of service, and reliability in meeting schedules. When carriers move freight, they are legally taking possession of the goods and are under obligation to deliver them for a reasonable price. In a free market, competition among carriers to provide this service theoretically helps keep transportation costs reasonable. A contract for service, known as a bill of lading, is used to specify the terms and conditions under which the cargo is to be delivered.

Service providers differ in the amount of freight they can transport and the distance they can transport it. Depending on the size and weight of the cargo, local freight within a city may be moved by courier service, delivery van, or truck. For movement from city to city, freight may travel by truck, barge, rail, bus (for small packages), or airplane. In many cases, freight is carried in large vehicles from city to city and then transferred to smaller vehicles for local delivery.

A major development in long-distance freight transportation since the 1950s has been the use of intermodal transportation carriers. Intermodal transportation is the combination of two or more transportation modes used to move freight from origin to destination. Intermodal transportation improves the transfer of freight from intercity movement to local distribution. An example of this is the combined use of trucks and trains to move cargo over longer distances. Truck trailers are loaded with goods, driven to a rail yard, and transferred to a rail flatcar. They are then moved a long distance by train, unloaded at the destination rail yard, and driven to a market or a supply warehouse. Such a freight trip is called trailer-on-flatcar (TOFC) or container-on-flatcar (COFC). Today almost 20 percent of all truck trailer loads traveling over 800 km (500 mi) in the United States are transported this way.

Intermodal transportation requires cooperation and agreements relating to prices and delivery arrangements among the different carriers. Similar agreements apply in the transportation of international freight. One way that shippers use technology to exchange information is by using electronic tracking devices and software. These tools allow shippers to monitor the progress of freight movement. Automatic equipment identification tags similar to bar codes are placed on containers and truck trailers for identification as they go through different stages of their trip.

B.

Passenger Service

Passenger service providers include airlines, bus companies, railroads, taxis, and other companies that transport people from place to place for a fee. Even though many people use personal transportation such as automobiles and bicycles, the for-hire passenger industry is an important part of the transportation system of many countries. In the United States, air travel is responsible for transporting the most passengers, with bus travel second and rail travel a distant third. This ratio is different for many other countries. In most European countries, for instance, passenger rail and intercity bus ridership are much greater than that of air travel.

Passenger service transportation within a city itself is commonly referred to as public transportation. The responsibility for providing public transportation is often shared between government and private companies. As cities grew in the 1800s, governments and businesses developed a form of shared transportation that would connect all parts of a city, creating the first public transportation systems. The first such service began in 1812 in Paris, France, with horse-drawn wagons called omnibuses. Although many of the early shared-transportation services were operated by private companies, these companies faced serious competition from other transportation modes. Many of these companies soon came under public control. In 1894 the first public transit commission was formed in Boston, Massachusetts. The first public takeover of a private transit company occurred in 1905, when New York City took over the Staten Island Ferry.

C.

Terminal Management and Planning

Terminals are transportation centers where goods and people are transferred onto and off of vehicles. Terminals include ports, airports, bus stations, and train stations. The greatest amount of delay in a trip often occurs at a terminal, usually because of congestion or inadequate capacity. Equipment failures and bad weather also frequently contribute to delays. Proper management and operation of terminals is crucial in order to keep passengers, vehicles, and freight moving efficiently.

Three forms of terminal management are commonly found in the transportation industry: government, private sector, and special authority. In some cases, such as with airports, one can find all three management structures in place. Government agencies often operate important terminals, especially in countries other than the United States. Terminal operation is organized to provide such necessary services as customer ticketing, package handling, and parking and docking for automobiles, trucks, aircraft, or ships.

Privately run terminals, such as freight terminals run by railroads, have similar organizational structures to those of publicly operated terminals but generally focus on commercial operation and managing the arrival and desired departure times of cargo. For private terminals, turnaround or transfer time is directly related to how much profit is made.

The third form of terminal management is a hybrid of the previous two. Governments create special authorities, such as port authorities for managing harbor operations, to manage and operate transportation facilities and terminals. Although such authorities are accountable to the legislative body that created them, they often have a great deal of flexibility in operation and finance. For example, whereas government agencies are nonprofit, many special authorities earn profits that are reinvested in the transportation system.

Planning for transportation facilities involves not only the government agencies responsible for transportation but also numerous users and stakeholders who depend on such service. The cost of airport expansion, for example, is often funded by increased landing fees charged to the airlines and ultimately to the traveler. Similarly, the costs of port improvements are often passed on to shipping companies and their customers. Thus, private companies are important participants in the planning and investment process for transportation improvements.

IV.

Trade and Economics

Many transportation innovations occurred because of the needs of the military. Nevertheless, advances in vehicle designs and infrastructure (such as bridges and roads) were soon applied to trade and commerce. The Roman road system, originally created to move troops quickly and efficiently throughout the empire, soon created a massive economic market centered on Rome. The European explorers of the 15th and 16th centuries were originally seeking new paths to the riches of the Orient when they happened on the New World. The trillion-dollar international trade business of today relies entirely on a reliable system of global transportation to meet demand and provide customers all over the world with goods and services.

International trade routes connect different countries. These routes reflect the economic interdependence of many nations of the world. Many countries are dependent on other countries for natural resources, finished goods such as automobiles and electronics, and parts for products assembled locally. Many of the world’s largest trade partners, such as the United States, Canada, Japan, Mexico, and Europe, are connected with numerous transportation services and travel routes. In Asia, Japan has strong maritime trade relations with Southeast Asian countries in order to exchange natural resources for manufactured goods. The U.S. ports of New Orleans, Louisiana, and Miami, Florida, are major ports of entry for trade with Latin American nations.

Treaties and international agreements among countries are used to protect international shipping and travel. These agreements have related to issues such as vessel standardization, allowable ports of entry in a nation, customs procedures, tariffs that can be applied to certain commodities, and rights of passage through international waters. A recent example of such an agreement is the North American Free Trade Agreement (NAFTA), which was signed in 1992 by the governments of Canada, the United States, and Mexico. Among other actions, NAFTA eliminated many tariffs, allowed Mexican trucks to travel into the United States, provided safety and regulatory standards for trucks and buses, and permitted U.S. and Canadian investment on a limited basis in Mexican transportation firms. Similar trade agreements will continue to characterize international transportation.

Besides the economic benefits associated with trade, there are many other indirect economic benefits related to transportation. More than 9.5 million workers are employed in transportation-related industries in the United States, and the transportation-related portion of the U.S. gross domestic product (GDP) in 2000 was $314 billion out of a total GDP of $9.9 trillion. Aerospace, naval, and automobile manufacturers are responsible for a large amount of that figure, as are the industries that supply these manufacturers, such as the steel, rubber, petroleum, and electronics industries.

V.

Government Regulation and Administration

The national government takes an active role in supervising a nation’s transportation systems. Transportation departments or ministries manage the planning, construction, funding, and regulation of these systems. Such government agencies study transportation needs and allocate resources in order to maintain the existing transportation systems and to anticipate future needs. The United States has an extensive system of government regulation, but, in contrast to what happens in other countries, most U.S. transportation services are privately owned and operated.

A.

Regulation in the United States

In the United States the federal government’s role in transportation is defined in the Constitution and in laws and court cases that have clarified and interpreted this role. The federal government regulates many important aspects of transportation, including transportation system planning, market competition, and vehicle design and safety. The government enacts laws that are intended to provide fair and competitive markets for transportation users and provides funding for construction of transportation projects. The U.S. Department of Transportation, an agency that is part of the president’s Cabinet, is responsible for the nation’s transportation system. Every state also has a department of transportation (DOT), and every county and city also has some organization with responsibility for local transportation.

The federal government allocates billions of dollars for transportation and raises that money in a variety of ways. In 2000 about $119 billion was spent by all levels of government in the United States just on road construction and maintenance. Over $7 billion was spent on public transportation. From 1982 to 1998 the federal government spent more than $38 billion for the construction and operation of airports. From 1945 to 1998 public agencies spent over $15 billion improving harbors and ports. The revenues to fund these expenditures come from three major sources: income, property, and sales taxes; special user taxes such as the gasoline tax and the airport use tax (the revenues from which are placed in trust funds to be used for specific transportation investment purposes); and user fees such as road and bridge tolls. Since the 1950s, user taxes have been the most important means of financing major highways, but costs are often greater than available funds. The gap between revenues and expenditures has been filled in two ways. One method has been to directly subsidize a given transportation program. The second has been to privatize services traditionally provided by government. Privatization can take several forms, from private operators providing transit services to private sources of funds being used to construct toll roads.

The planning and construction of state transportation systems is the responsibility of the state DOTs, and the planning for metropolitan transportation systems is the responsibility of metropolitan planning organizations. By federal law, every state and metropolitan area in the United States must have a transportation plan. The actual construction of transportation facilities is done through contracts with private construction companies.

Although much of the U.S. transportation system is operated by private interests, in some special cases government agencies operate or provide overall control of transportation systems. Urban transit services in the United States first started as private businesses, but as a result of serious financial problems in the face of competition, most services today are operated by public agencies. Government agencies also provide traffic control for some transportation systems. The Federal Aviation Administration (FAA) provides two types of air traffic control services. The agency operates air traffic control towers at 545 airports, providing instructions for landing and departing aircraft. It also operates 21 air route traffic control centers throughout the country that guide aircraft along flight routes.

Many government agencies play important roles in regulating the safety and environmental aspects of motor vehicles. The U.S. Environmental Protection Agency (EPA) regulates the permissible levels of pollutants that may be emitted from motor vehicles. Other agencies regulate safety and fuel efficiency requirements. The federal and state governments provide traffic control rules and regulations that dictate how motor vehicles are to be operated, and the federal government issues manuals and guidance that assure uniformity in the use of traffic control devices from one state to another. Various other agencies regulate rail, air, and maritime transportation.

B.

Regulation in Other Countries

The role of government in transportation varies from country to country depending on local tradition and legal precedent. One of the biggest differences between the United States and other countries is the role of the private sector in the operation of transportation services. Federal, state, and local governments have a significant role in the U.S. transportation system, and businesses in the private sector generally maintain the provision of service and the use of that system. Private firms own and operate the railroads, airlines, water transportation companies, pipeline operators, and motor carriers. In most other countries, such as the countries of Europe and Asia, the major transportation service providers are often state-owned. In many countries where the transportation system was developed under colonial rule, the country’s independence was accompanied by the nationalization of the railroads and airlines. The governments of these countries have provided heavy subsidies to their transportation services. Many of these governments are now experimenting with privatizing these services in order to reduce costs.

VI.

History

The history of transportation is largely one of technological innovation. Advances in technology have allowed people to travel farther, explore more territory, and expand their influence over larger and larger areas. Even in ancient times, new tools such as foot coverings, skis, and snowshoes lengthened the distances that could be traveled. As new inventions and discoveries were applied to transportation problems, travel time decreased while the ability to move more and larger loads increased. Innovation continues today, and transportation researchers are working to find new ways to reduce costs and increase transportation efficiency.

A.

Animals and the Wheel

The domestication of animals was the first great leap in transportation ability. However, the use of animals to pull vehicles or to carry riders had to await several important inventions. At first, oxen and horses were harnessed to vehicles by neck straps, which tended to choke them when they pulled heavy loads. Finally, around ad 500, someone devised a padded collar that rested on the animal’s shoulders. The use of such a collar increased the amount of weight that the animal could comfortably pull. Horse stirrups were in use in India and Asia by around 200 bc, allowing riders to maneuver their horses more effectively. Saddles were introduced in Europe around ad 200. Horseshoes, used to protect the hooves of a horse, were in widespread use by about 700.

The first major innovation in wheeled transport was the spoked wheel. By using a spoked wheel instead of one made of solid wood, faster and more maneuverable vehicles could be designed. Protruding copper nails placed in the wheel to provide greater traction were introduced around 2000 bc. Iron rims fastened to the edges of wheels were introduced in 700 bc. These rims increased the strength and durability of the wheels. The harnessing of multiple animals to a single vehicle began around 100 bc. These innovations all contributed to increasing the weight that a wheeled vehicle could carry.

The wheel, when applied in wagons and carts, was the first transportation innovation to create the need for roads that could survive repeated use. Early roads built—usually by slaves—in Rome, India, Persia, and China were made of brick or stone. These ancient roads fell into disrepair during the Middle Ages. However, the resurgence of travel and trade during the Industrial Revolution in the 18th century in Europe created the need for additional roads and new methods of construction. The most important innovation was the use of well-compacted, small stones in a soil foundation. Called macadam, after its inventor John Loudon McAdam, this new type of road construction simplified road building and enabled many kilometers of new roads to be built.

B.

Water Transportation

Oars and sails represent the two early advances in water travel, increasing both ship speed and reliability. With oars, ships could be rowed against the current and could still move even if facing unfavorable winds. With sails, ships could harness the tremendous energy of the wind to travel long distances. One of the most important early discoveries was the lateen sail, a triangular sail that could convert side winds into forward force. The lateen sail allowed ships to sail against the wind, or tack. It was the major sail technology used by seafaring people in ancient times. The stern rudder, which allowed greater control of ships, replaced the side steering oar in the 8th century ad in China and in the 12th century in Scandinavia.

In navigation, great advances were made that allowed ships to venture to sea and safely return. Early oceangoing ships generally stayed close to shore, but by the 100s bc, primitive astrolabes had been developed to help determine latitude. Thus, seafarers could determine their position at sea. The astrolabe was succeeded by the octant, and in 1757 the sextant was invented. The sextant remained the most accurate device to measure latitude until the 20th century. To determine direction when visibility was poor, the Chinese used a lodestone spoon spinning on a bronze plate as an early compass. By the 12th century the magnetic compass was being used as a navigation aid. With the increasing sea exploration of the world that began in the early 1400s, the art of mapmaking blossomed. With accurate maps, explorers could find their way when their location was checked against known landmarks. See also Map: History of Maps.

The most important technological development for inland water transportation was the invention of the canal lock. The lock connects stretches of canal built at different elevations. Although a simple canal lock was used by the Chinese as early as 984, the most extensive use of locks was found in Holland, where usable locks were in operation by 1373. Italian engineers invented the pound lock in the late 1400s. As the forerunner of today’s two-gated lock, the pound lock allowed ships to enter one end of a canal and, after water was added or removed, to exit at the other end at a different water level.

C.

Steam and Internal-Combustion Engines

The development of the steam engine in the 18th century revolutionized transportation on both land and sea. The first steamboats were very simple designs with large paddle wheels that provided the ability to move against the current. Not until iron-hulled ships and the more efficient screw propeller were developed in the late 1800s did steam-powered ships begin to dominate world trade routes. With the reliability and capacity of the steamship, global markets tied together by transportation links became a reality. Ship designs became customized to carry specific types of cargo. For example, tankers were designed for carrying liquids, bulk freighters for general cargo, and, more recently, ships were designed to handle containers.

The steam engine, when applied to railroads, increased dramatically the freight- and passenger-carrying capacity of a nation’s transportation system. Improvements to the steam power plant greatly increased steam pressures. Perhaps the greatest innovation occurred in the railroad track itself. Early railway tracks were built of long wooden rails with iron straps fastened to the tops. This design soon became obsolete because of its inability to carry heavy vehicles. In the mid-1830s this design was replaced with the T-shaped iron rail still used today. In addition, the adoption of a standard gauge, or track width, provided continuity in rail service from one location to another.

One of the major technological advances in rail transportation was the development of the diesel locomotive. As compared to the steam engine, the diesel locomotive engine required less maintenance, used fuel more efficiently, was quicker to start, and reduced the amount of soot and pollution in cities. First used in 1925, the diesel locomotive had replaced steam engines in the United States by the late 1950s.

As important as the railroads were to transportation history, the internal-combustion engine had an even greater effect. The engine powered the automobile, introduced in the early years of the 20th century, and forever changed the way people move from place to place. Several innovations in the motor vehicle itself were necessary before it became the common method of transportation used today, as early automobiles were less than convenient. Gradual improvements such as the automatic starter, safety plate glass, pneumatic tires, hydraulic brakes, improved suspension, and automatic transmission each made the motor car more appealing to the consumer. New production methods revolutionized manufacturing worldwide. American industrialist Henry Ford’s large-scale adoption of the assembly-line production process in 1913 greatly increased production and made the automobile a form of personal transportation that millions of ordinary people could afford.

The internal-combustion engine also had a significant effect on air travel. Early steam engines proved too heavy for practical air travel. The first airplane flown by the Wright brothers in 1903 was powered by a gasoline engine. Subsequent development of the jet engine allowed even greater speeds and distances, making possible world travel within a 24-hour time period.

D.

Recent Trends

Recent innovations in technology have been driven by a desire to find safer, faster, and more reliable means of getting from place to place. For passenger transportation, speed and convenience are primary goals. For freight transportation, speed, reliability, and efficiency, or carrying more cargo for less money and arriving on time, have been the motivating factors.

Several technologies that are shaping society in a variety of ways will likely characterize the future of transportation. Intelligent transportation systems apply the latest advances in computers and electronics to better control vehicle operations. Computerized road maps used with the Global Positioning System (GPS) help drivers to navigate. Companies that use fleets of vehicles, such as delivery companies, can use satellite technology to monitor the location of their vehicles at all times and improve efficiency.

Research is also being conducted into improving the materials used for transportation vehicles and infrastructure. Composite material, which is a hybrid consisting of many different component materials, can provide lightweight, extremely strong, and highly durable material for vehicle construction. With the lighter weight, vehicles can become more fuel efficient. New materials for pavements and bridges will also provide for stronger and longer-lasting infrastructure.

Fuels and propulsion technology are other important areas of research and innovation. Most modern transportation systems rely on petroleum for energy, but this source of energy is finite and creates serious environmental effects when used in the internal-combustion engine. Research into alternative fuel sources, such as electrical storage, natural gas, methanol, ethanol, fuel cells, and solar energy, will continue in order to ensure a reliable supply of energy for the transportation systems of the world. Several new forms of propulsion are also being investigated. For example, magnetically levitated trains, in which magnetic forces lift, propel, and guide a vehicle over a guideway, are being developed in Germany and Japan. Such trains have achieved speeds up to 500 km/h (300 mph).