In a macroeconomic sense, transportation activities form a portion of a nation's total economic product and play a role in building or strengthening a national or regional economy and as an influence in the development of land and other resources. In a microeconomic sense, transportation involves relations between firms and individual consumers. The demand for and supply of transportation for both passengers and freight, transportation pricing, and the reasons why the transportation system is both regulated and deregulated are among its concerns. Finally, the government's (government) involvement in each mode of transportation differs. In some instances private enterprise is used; in others, government provides the facilities and equipment, especially if the rationale for government involvement is that a strong transportation system is necessary for developing the nation's economy or for its defense. Government's involvement in transportation has both a macro- and a microeconomic significance.

According to the United States Bureau of Labor Statistics, in 1989 the typical household spent $27,810. Housing accounted for $8,609; transportation (mainly automobiles) accounted for $5,187; and food accounted for $4,152. Looking at the age of consumers, those under 25 spent the highest proportion of their income, after housing, on transportation; presumably much of this went for automobiles and for automobile insurance premiums. By almost any measure, the great significance of transportation to individuals and, aggregated together, to society is apparent.

Figures for the United States are not representative of the world. Automobile ownership rates are not as high in other countries.

Transportation facilitates communication and commerce. Alexander Hamilton, secretary of the Treasury in the 1790s, believed that internal improvements were necessary for the nation's economic growth. The word “infrastructure” is used to describe all the facilities that an economy has in place, including its transportation network of roadways, railroad tracks, and ports, as well as the vehicles and vessels to use them. An adequate infrastructure is a prerequisite to economic development. Transportation and communications are important in developing and strengthening social, political, and commercial ties. These ties must be developed before trade can be handled on a regular basis. Transportation also is necessary for goods to reach markets where they can be sold or exchanged for other merchandise or services. Transportation undertakings have proved to be a fertile ground for inventors, innovators, entrepreneurs, and their supporting investors. Much of the dynamic growth in the United States and other countries in the 20th century can be attributed to transportation.

Many episodes in the history of the United States illustrate the dependence of the developing lands upon a transportation system. During the Whiskey Rebellion (1794) farmers in Pennsylvania converted their corn to whiskey because they had no other way of transporting their bulky corn crops to market. Construction of the Erie Canal from Albany to Buffalo, in New York, opened up the Great Lakes. Settlers went west, and, in a few years, their farm products started moving east. There followed a canal-building frenzy that lasted until the Civil War and a railroad-building frenzy that lasted until near the end of the 19th century. Settlers wanted to be near a canal or rail station so that they could sell their crops. In the 20th century the focus shifted to building roads and airports. Paved roads were needed by farmers to reach markets and to allow trucks and automobiles to travel between cities. Airports also became important as cities wanted to be served by airlines.

Transportation allows each geographic area to produce whatever it does best and then to trade its product with others. In addition to direct, or back-and-forth trades, it is also possible to use transportation to link together a number of different steps in the production process, each occurring at a different geographic site. Speedy modes of transportation (such as air) allow perishable foods to be distributed to wider market areas. Transportation also allows workers to reach their job sites. Lastly, because of transportation, it is possible for a producer to reach a large number of markets. This means that the quantity of output can be large enough that significant production economies of scale will result.

A transportation network makes markets more competitive. Economists often study resource allocation—that is, how specific goods and services are used. A transportation system improves the allocation process because it widens the number of opportunities for suppliers and buyers.

A transportation network also adds to a nation's military strength. One reason is that, by strengthening the economy, transportation places the nation in a better position to weather adversity and to produce materials necessary to sustain its economy and military strength. If the nation actually embarks upon war, its transportation system is useful in moving troops. During the War of 1812, the British invaders could travel on ocean ships and attack wherever they chose. The U.S. Army could not move as quickly on land and had trouble keeping up with the British invaders. After the War of 1812, the U.S. government drew up plans for an extensive network of canals along the East Coast that could be used for defensive troop movements. Some of these canals were constructed, although canal construction was eventually halted for other reasons. In the early days of World War I, German strategy involved eliminating Russia from the war in the first few weeks, then shifting the massive German army west, by rail, in an attempt to defeat France. In the mid-20th century, the United States began construction of its interstate highway system, the proper title of which is “The National System of Interstate and Defense Highways.” Clearances above the roadway on this interstate system were high enough to allow passage of trailer-drawn military missiles used in the 1950s. (Experience in World War II showed that it was more difficult to permanently damage highway systems than it was to damage railroads.)

Initially, transportation's role with respect to natural resources was that it allowed resources to be developed or used. Too much of this occurred, and it has resulted in resources being misused, overused, or exploited as well. Transportation also has made it possible to strip forests of trees, with or without regard for environmental (environment) effects on the cleared land or adjacent surface waters. By opening up markets for products, transportation has resulted in lands being converted from a natural state to agriculture. The value of farmland has always been related inversely to the distance to markets. In today's society, the value of home sites in suburbs is inversely related to the travel times and costs associated with reaching offices and stores in the central city. Patterns of land development in most of the United States were influenced by the land survey requirements enacted in 1785 for what were then the western lands. Townships were laid out in six-mile-square sections; this checkerboard pattern may be seen when flying over the Midwest and prairie states. One section in each township was set aside for education, and this section became the site of a school and often of a small community.

As railroads grew in the mid-19th century, development followed. Studies of population clusters in the Midwest show them located along railroad lines. As major cities expanded, streetcar lines attracted development. Streetcar firms were sometimes bribed by land developers to have new lines serve their undeveloped land, thus increasing its value. Today, roads and freeways influence patterns of suburban growth. They have made it possible for the middle class to flee the central city. Individuals who oppose further growth actively oppose politically any transportation improvements that might open up their area to more development.

Lands often contain mineral and oil resources, and transportation systems have allowed their exploitation. Some of the largest tonnages of products moved in the United States are products of mines, such as iron ore and coal. In ocean shipping, petroleum is the largest single cargo carried. The transportation system itself is the largest consumer of petroleum products; in the United States, highway vehicles consume just over half of all the petroleum. Since petroleum prices escalated in the early 1970s, there has been increased concern with the fuel efficiency of different types of transportation. As petroleum prices decline, interest in fuel efficiency slackens, and automobiles are used more and mass transit less.

Construction of transportation facilities was, in itself, destructive to the environment, but over time the adverse environmental impacts have been tempered somewhat. The best large-scale example is the Trans-Alaska Pipeline, built in the 1970s, whose routing was altered to avoid blocking migration patterns of certain species of wildlife. The construction of sound-deflecting walls near urban freeways and soundproofing structures near airports has helped to control noise. Federal regulations are phasing out the use of noisier aircraft engines.

Disposal of old and abandoned automobiles has caused another land-use problem. Some automobiles are abandoned on streets or in fields; and salvage yards are unsightly. The combination of materials used to construct automobiles often discourages recyclers from paying very much for junked cars to turn into scrap for sale and reuse.

Transportation also has altered water resources (water resource). For centuries, wetland areas in ports have been filled in for cargo handling and industrial facilities. Dams and locks have been built to harness major rivers. Flowing streams were used to carry away urban and industrial wastes before sewage treatment plants were constructed. Harbours and navigation channels must be continually dredged to remove accumulated silt. Often this dredged material is polluted, and controversies arise as to where it can be placed so as to minimize damage to the environment. Loading and unloading of dry bulk cargoes generates dust, and port facilities must install extensive systems to collect dust particles. Oil spills are usually contained now before a major disaster occurs, although every year or so there is a major oil spill somewhere in the world.

Air resources are adversely affected by the pollutants generated by the engines that power vehicles. In the United States, the problem is most acute in the Los Angeles area, well-known for its smog. Pollutants come from other sources as well, but transportation is usually acknowledged to be the major villain. Steps are being taken to lower the emissions generated by automobiles and to change driving and commuting patterns to use fewer vehicles. Automobiles are being modified to produce fewer pollutants. There is increased interest in electric automobiles because they generate almost no air pollutants. However, it is possible that the electricity used to recharge their batteries would be produced by a means that generates air pollution. Nonhighway types of transportation also produce air pollutants.

Transportation has increased each person's mobility. Initially, one could walk about 20 miles a day; using a horse or bicycle would double or triple this range. Today one can travel halfway around the world in a day. Through increased mobility, one's range of acquaintances can be worldwide. Business and professional interactions also can be on a worldwide basis. With such wide-scale travel opportunities, business and culture will never be the same.

In terms of sociology, teenage people in the United States view obtaining a driver's license as one rite of passage toward adulthood. The automobile is a means for them to escape parental supervision. The automobile is blamed for the decline of small towns; persons with cars are able and willing to travel longer distances to the stores and other attractions of larger communities. In the United States, the school bus also led to the decline of small towns, because it made it possible to consolidate numerous small schools. Hamlets where small schools were closed went into decline.

Transportation has increased employment opportunities, because one can travel to reach more potential jobs or a sales or professional person can cover a wider territory. In sparsely settled areas, for example, veterinarians and physicians make calls using small aircraft. Transportation activities also provide employment opportunities: working for carriers and shippers, constructing vehicles and roadways, and working in government agencies involved with transportation.

However, as transportation facilities and opportunities increase, there are some groups left behind. The poor, the feeble, the elderly, and the disabled are in danger of being bypassed because they lack equal access to transportation systems. In many locations in the United States, automobile ownership and use is virtually a requirement. Society is uncertain as to what responsibilities it has for transportation systems that can be used by those without automobiles.

Another negative impact relates to injuries and deaths caused by transportation. While airline crashes receive the most publicity, highway accidents cause a tremendous number of fatalities and injuries. Fortunately the number is decreasing owing to considerable improvement in auto safety. This includes safer roads, lower speed limits, use of seat belts, and stricter enforcement of laws against driving while intoxicated. Automobiles feature improved and often governmentally required safety equipment.

Transportation is supplied by individual firms of all sizes and by government agencies. The range of government involvement differs by type, or mode, of transportation and the geographic or political areas of jurisdiction. Governments are involved in providing transportation because it is necessary for economic development, for carrying out certain other functions of government (such as public safety or making it easier for individuals to reach schools or hospitals), and for national defense.

In the United States, airlines are run as private firms, while airports and the air traffic control network are supplied by government. Motorists and trucks operate in the private sector and travel on highways provided by the public, largely through taxes collected on motor fuels. Barges and Great Lakes carriers and oceangoing ships are private-enterprise operations, paying low levels of user fees. They travel on waterways improved and maintained by governments. Railroads are private-enterprise ventures operating on their own roadbed and track. An exception is intercity rail passenger service, which is provided by a government agency. Oil and gas pipelines are operated by private enterprise. Mass transit operations carrying large numbers of passengers in urban areas on buses, light rail vehicles, and ferries are usually operated in the public sector. At one time mass transit was provided by the private sector, but private firms could not survive much beyond World War II, when automobiles became popular. Communities, later aided by the federal government, bought out the declining private transit operators and replaced them with public-enterprise operations. Vehicles, aircraft, and ships are usually built by firms in the private sector.

Outside the United States, public ownership and operation of transportation is quite common. Most nations own and operate their railroads and airlines. Automobiles and trucks are built in the private sector, but roads are provided by the public. Ships may be either publicly or privately owned, although virtually all nations subsidize their merchant marine.

So, in the supply of transportation services, a mix of public and private entities is usual. Private firms are responsive in situations where there is a profit to be made. If the market will not support profitable operators, a variety of government subsidization (subsidy) schemes are used. Ideal schemes allow the subsidized operator to develop business to a point at which the subsidies are no longer needed. Frequently this does not happen; the users—or the employees—of the carrier enjoy the subsidies and assert political pressure on governments to maintain them. Governments are confronted by groups who demand certain levels of transportation service but are unable, or unwilling, to pay for them. Subsidized carriers then pursue objectives that may differ from the aims of economic efficiency. This leads to a redistribution of income from the general taxpayer to the user of the subsidized transportation operation. Subsidized transportation also affects decisions made by firms determining where to locate plants or by individuals determining where to locate homes. Both groups in making these decisions attempt to minimize transportation costs that they must pay. If the costs these groups must pay are not the same as the true and total costs to society, the low-transportation-cost site in their eyes is perhaps not the same as might be chosen by one knowing—or having to pay—all transportation costs.

A form of investment analysis for long-range government investments is benefit- cost or benefit-to-cost analysis. It is more widely used for transportation undertakings than for other public-sector investments. Long-term projections of benefits and costs are made. These future flows are then discounted, through use of a rate of interest, back to the present value. (For example, using a 5 percent compound interest rate, $1,000 10 years in the future is worth $614 today.) Costs of a project include land—such as that needed for the right-of-way—site preparation and construction of the facility. Future operating costs of the facility also must be considered.

Benefits are usually savings in travel time for passenger-oriented projects and savings in transportation costs for freight. An example of this would be dredging a harbour. If the plans would permit a larger vessel to be used, the costs per ton for shipping would be lowered, and this would be considered a benefit. Benefit-cost analysis can be applied to a variety of projects and, if similar assumptions are used in performing the analysis for each, then the projects can be ranked in the order that should be used for getting the greatest return for the governmental investment.

In the United States, so much transportation is conducted with private automobiles that passenger transport could almost be equated with automobile transport. The most common trip is the journey to work, a to-and-fro movement 5 days each week, 50 weeks per year. The individual concerned may have chosen both a job and a home while thinking of the daily journey that would have to be conducted between the two. In the United States, the vast majority of journeys to and from work take place in private automobiles, often with the driver alone, carrying no passengers. Car pools are encouraged in most large urban areas by setting aside certain lanes on freeways in and out of the city for use by vehicles carrying multiple passengers. On toll roads and bridges, and at freeway entrance points, they may also receive preference.

There is also work-related travel, which may be conducted in any sort of vehicle. The demand for such a trip must outweigh both the transportation costs and value of the individual's time spent while traveling. Some individuals travel in search of work. There also are migrations of people from one part of the country to another, seeking a job and a better life. There have been, and will continue to be, large migrations throughout the world.

Travel to and from school is a regular movement for many people. Buses may be provided by the school district, or public transportation may be used. Individuals also need transportation for shopping, visits to doctors, visits to friends, and other personal reasons. Some persons travel for religious purposes on pilgrimages to sites of special significance. Vacation and pleasure travel form another demand for transportation services.

Individual demands for transportation can be aggregated into demands for larger vehicles. Examples are commuter trains that operate near large cities or aircraft that fly coast-to-coast or across the ocean. Most passengers have several alternative modes of transportation or carriers from which to choose. A commuter may drive alone, be part of a car pool or a vanpool, or ride on a bus, ferry, or train. Part of the person's decision as to type and size of vehicle is based on the value of his or her time and the relative comfort and convenience associated with travel in each vehicle type.

Demand for freight transportation is generally a function of demand for a product. A simple definition of demand for freight transportation is that it reflects the difference between a commodity's value in two different markets. If oranges are worth $4 a bushel in Florida and $10 a bushel in Chicago, then the demand for transporting oranges from Florida to Chicago is expressed as $6 a bushel. As oranges begin moving from Florida to Chicago, the spread in market prices will start to decrease and will eventually drop to the point where it no longer covers the costs of transportation.

Freight is time-sensitive. Fresh seafood is perishable; newspapers must be delivered promptly. Shippers have money invested in inventory and often want to use faster modes of transportation to reduce the amount of time they must wait for payment.

For some goods, the cost of transportation is nearly the same as the cost of the product, and it thus influences demand for both the product and its carriage. Steel-mill slag (a by-product of the steel-making process) has almost no market value, and sometimes steel mills must pay to have it carried away. It can be used as an aggregate in concrete but competes with other materials, such as sand, which are very low in cost. Many recycled products also have almost no market value, and transportation costs become the major factor viewed by those who may want to buy the recycled products for some subsequent use.

Sites for economic activity are selected after taking into account factors such as nearness to sources of supply and to markets, availability of labour, climate, taxes, and transportation. One criterion for selecting a factory site is to find a spot between the sources of raw materials and markets where the total of all transportation costs is minimized. Other concerns include the number of carrier firms serving a site, the rates they charge, and the quality of service that they offer.

Users of transportation have several yardsticks when measuring the quality of transportation service between two points. They are speed; accessibility, measured in lapsed time between the decision to use transport and obtaining access to it; reliability; frequency of the user's trips; intervals between the carriers' departures; minimized transfer or intermediate stopping points; and punctuality.

Carriers set their rates between two limits. The upper limit is the value of service to the user, meaning that, if the carrier knew the true value of the service to an individual shipper or passenger, that is the amount they would charge. They could not charge more than the value of service, because the customer would not use it. Carriers would like to analyze the needs of each potential user and place each in a group where the charges would equal the total value of the transportation service. Carriers cannot do this, but they do place users into groups. Airline passengers sitting in the same row on a single plane may each pay a different fare, depending on how far in advance they were willing to buy a ticket and what kind of restrictions on the use of the ticket they were willing to accept. Freight shipments also are divided into many classifications, and one factor influencing the freight rates is the value of the product, with higher-valued products paying more. Part of the rationale for this is that higher transportation costs have less impact on an expensive good's final selling price; hence they can stand to pay the higher rates. In a sense, they help subsidize the carriage of less valuable freight.

The lower limit of a transportation rate is the cost of service—that is, the carrier should not charge less than the cost of service or it will lose money on the business. It is difficult, however, for many carriers to know or determine their costs. Railroads and pipelines have large overhead, or fixed, costs. These are costs to which the carrier is already committed without regard to the level of current business. The other form of cost is known as out-of-pocket, or variable, costs, that are related to current business. If a shipper wants to ship four railcars of freight, the railroad's fixed costs—e.g., interest and taxes on its roadbed—continue without regard to whether the railroad decides to move the shipper's four cars. If the railroad decides to move the cars, it incurs variable expenses, such as fuel for the engine and salary for the crew. The shipper may be willing to pay only a little more than the variable costs. The railroad will consider any payments received that are greater than its variable costs as a contribution to overhead.

Even the distinction between overhead and variable costs is subject to debate. With respect to the shipper with four freight cars, it might also make a difference whether the direction he wanted to send his freight was the same as most railroad traffic (a forward haul) or a flow in the reverse of the major haul (a backhaul). If the shipment is a backhaul, the railroad might have been planning to move empty cars anyway, and the variable costs of moving the shipper's freight might be only the costs of moving loaded, rather than empty, cars.

Carriers are often uncertain how to determine the costs of individual hauls. An American railroad does not know how much of its overhead costs to allocate, for example, to a shipment of coal from Cheyenne, Wyo., to Duluth, Minn. Sometimes the concepts of “joint products” and “by-products” are used. A joint product is essential to the long-term survival of the firm, while a by-product is nonessential. The carrier must have a strategy to keep the joint-product types of traffic and be certain that their rates on this traffic are compensatory.

Carriers also enjoy economies of scale (economy of scale), although this varies with mode of transportation. Railroads benefit the most; a stretch of track between two cities has the same fixed daily costs whether it handles 1 or 10,000 cars per day. Airliners have a break-even point, at a load of about 70 percent of capacity. Revenues from any passengers carried above this amount flow almost directly into the firm's profits. A carrier enjoying economies of scale tries to increase volume by lowering rates to attract additional traffic. In transportation, the phrase “economic density” is used to describe benefits to carriers of having certain heavily used routes that are full, or dense, with traffic.

If the shipper plans to use a motor carrier rather than a railroad, the motor carrier is likely to ignore completely the costs to the public of building and maintaining the highway and concentrate solely on the costs of operating the truck. It may be that the motor carrier contributes taxes that help improve and maintain all highways, but that is not likely to affect day-to-day business decisions concerning whether to haul specific loads of freight for a customer.

A carrier's “ideal” rate would maximize a figure that represents a volume of traffic expressed in units multiplied by a rate per unit that is higher than costs. To maximize that figure, either a large volume of traffic units or a wide gap between revenues and costs per unit is needed.

Associated with carrier costs are costs of congestion. Most people like to travel at certain hours or on certain days; the same holds for some types of freight. This phenomenon is known as peaking. Carrier costs increase during peak periods because they must provide extra equipment. Congestion itself adds to operating costs because vehicles may not be able to depart on time and must move slowly because of heavy traffic. Because of these added costs associated with congestion, many carriers charge more for operations during peak hours. The increased charges reflect two factors: the carrier's higher costs and higher demand by passengers and shippers. Most users are willing to pay higher charges for service during peak periods even though they also incur additional costs in terms of waiting time.

Carriers charge lower rates for “off-peak” periods. This reflects their lower costs and is an effort to entice users away from the peak periods. Mass transit systems often charge lower fares from 9:00 AM until 3:00 PM on weekdays, for example, encouraging shoppers to travel when a system is not filled with commuters. Carriers have “incentive” rates to encourage increased utilization of equipment, and they will charge less per unit of weight for larger shipments.

User charges are fees levied for using transportation facilities operated by government agencies. Aircraft pay landing fees to use airports, and vessels pay dockage and wharfage fees to use public port facilities or lockage fees to transit locks along a waterway. Motorists and trucks pay fees to use toll roads or toll bridges.

For many years, the economic practices of much of the transportation system in the United States were regulated. Today, interstate pipeline and some interstate railroad traffic is regulated, as is intrastate motor carriage in most states. At one time, nearly all intercity transportation was subject to economic regulation. The railroads (railroad) came under federal regulation in 1887 to curtail abuse of their monopoly (monopoly and competition) powers. They were the first large monopolies in the United States, and society was not certain how to protect itself from them. Strict regulations, enforced by the Interstate Commerce Commission, controlled rates and provided that railroads could not charge more for a short haul than for a long haul over the same route. This latter rule was to overcome a railroad practice of charging low rates between major cities where several railroads competed, subsidizing this competition by charging high rates to intermediate points served by a single railroad. Regulators tried to make railroads set rates that were “fair” to all users and to the communities and industries that the railroads served. Entrance into and exit from the industry was also controlled.

The nation's oil pipelines (pipeline) were regulated in 1906, as a reaction to John D. Rockefeller's use of them as a tool for monopolizing the oil industry. Some motor carriers were regulated in 1935. In this situation, the problem was too much competition, rather than too little. Truckers (truck) engaged in what was referred to as “cutthroat” competition. They charged rates that did not even cover their operating costs and tried to make up for this by avoiding maintenance on their trucks and tires and driving long hours. Motor carrier regulation attempted to provide stability to the industry, although not all motor carriers were subject to regulation.

In 1938, domestic airlines were placed under the purview of the new Civil Aeronautics Board, which regulated routes, service, entry and exit, and rates. Some segments of the inland waterways industry were regulated in 1940. Freight forwarders—intermediaries who accepted small shipments from many shippers and consolidated them into larger shipments to tender to carriers—were regulated in 1942. In 1948 carrier rate bureaus, committees representing carriers that would meet to agree on rates for the industry to charge, were given immunity from antitrust prosecution.

In the post-World War II era, it became apparent that regulation was not working well. Those segments of the truck and inland waterways industry that had not been regulated grew in size and took considerable traffic away from the railroads. Most railroads in the Northeast were bankrupt. One of these was the Penn Central, and, in financial terms, this had been the nation's largest bankruptcy to date. In some transport modes, the workers' unions were very strong, and management would award union members wage increases which the regulatory body would then allow carriers to pass on to shippers as increased rates. In markets where rates were set by regulatory bodies, the carriers did compete, but not by driving costs down; instead, they would add services and increase costs up to the point at which they equaled the regulatory agency's approved rate. About 1970, the United States passed a number of laws that removed many economic regulatory shackles from the nation's carriers. Included in this wave of deregulation were airlines, motor carriers of freight, railroads, intercity buses, and household goods movers. Deregulation has caused difficulties for carriers and carrier labour. Individual carriers, and the industries they are part of, are not as stable as they were prior to deregulation. Many carriers have gone bankrupt, and carrier labour has lost much of its economic and political clout. However, and as a result, charges for freight and passenger carriage have dropped.

In addition to economic regulation, all levels of government regulate transportation safety and movements of hazardous materials. Testing transportation operators to detect possible drug use is a controversial matter. States also limit the lengths, weights, and axle spacings of heavy trucks.

Economic regulation is handled differently in various other countries. A common pattern is for the government to own the railroads and airlines and to restrict other carriers if they appear to be capturing traffic from the government operations. International airline operations and services are regulated by strict treaties between the nations exchanging airline service. Actual fares are established by the International Air Transport Association (IATA), a cartel (or organization) of all the world's air carriers. Cartels known as conferences also regulate the rates charged by ocean liners that carry cargo on a regular basis. Each conference is made up of member lines that serve certain routes, say, between U.S. gulf ports and ports along the Baltic. Over the years, the U.S. government has attempted to control practices of both airline and ocean liner cartels serving the United States, but it has had limited success because it must share jurisdiction with other nations.