The trucking industry is made up of those persons and firms engaged in the business of owning and operating motor trucks for hire to transport products over roads. Such companies are known as carriers. CLASSIFICATION OF CARRIERS The three principal categories of carriers are: private carriers, who use trucks to transport only their own products from farm to market, or raw materials from source to processing or manufacturing plants, or finished products to their markets, or for interplant movements; contract carriers, who enter into contractual agreements, usually long-term in nature, with business establishments to transport materials and products for those firms; and common carriers, who serve the general public on any and all commodities. A contract carrier may contract with several firms; however, shipments from different firms cannot be mixed together. Common carriers are granted operating certificates by the \TInterstate Commerce Commission\t (ICC) as either irregular-route carriers or regular-route carriers. Irregular-route carriers serve the public on "call and demand." They usually operate from a central office or terminal, shipping either specified commodities (such as textile products) or general commodities from specified points or areas to other specified areas. Regular-route common carriers are granted authority by the ICC to operate over specified highway routes on a regular basis, using terminals located strategically to consolidate and distribute freight in a surrounding area. Commodities handled by regular-route carriers may be specified, or the carrier may have authority to handle general commodities, usually with some exceptions for which special and specific authority must be granted by the ICC. Such special goods include small-package express, armored express (for transporting items of unusual value), household goods, automobiles, explosives, liquids carried in tank trucks, dry bulk goods, logs, and cement. Agricultural produce (unprocessed farm products) is not subject to ICC regulation and may be handled by what are known as unregulated motor carriers. The ability of a truck to pick up produce from several farms and bring it quickly to market makes trucking well suited for this purpose. HISTORY The first load-carrying, self-propelled road vehicles were vans hauled by steam engines. These vehicles, which were experimented with throughout the 19th century, first appeared in discernible number in Great Britain in the 1870s. In 1892 the Frenchman Maurice Le Blanc introduced steam-powered cartage vehicles for commercial users (Paris department stores). Karil \TBenz\t's invention (1885) of the gasoline-powered internal-combustion automobile spurred the development of a similarly powered load-carrying vehicle, the first example of which probably was produced (1896) by the German engineer Gottlieb \TDaimler\t. Early trucks were relatively heavy and had crude mechanisms. They were confined to city deliveries and hauling, because they could not manage the mud and potholes of outlying roads. In 1903 the Automobile Club of America staged the first U.S. commercial-vehicle contest to test the economy, reliability, durability, speed, and carrying capacity of the truck--the newest mode of freight transportation. Stimulated by the results of that contest, the manufacture and use of motor trucks flourished. By 1908, 4,000 trucks were in use in the United States, transporting goods of every type wherever streets and roads were passable. By the start (1914) of World War I, 300,000 trucks were in use, and by the war's end (1918) there were more than a million. By 1915 most manufacturers had settled on a conventional construction in which the engine was located ahead of the front wall of the cab. Early trucks resembled horse-drawn wagons of the 19th century. They lacked roofs, doors, and windshields; nothing protected the driver from the elements. The vehicle was driven on the right side. TIRES were of solid rubber. The ride was uncomfortable but bearable because the top speed was only 32 km/h (20 mph). Then came roofs, roll-down curtains, windshields, doors, and side windows. By 1930 most truck cabs were fully enclosed. Few modern (as opposed to steam-engine-hauled) trailers were built before 1915. The first type of modern trailer used was the full trailer, defined as a towed trailer whose entire weight rests on its own axles. By 1920 the semitrailer, whose front end rests on the rear portion of the hauling truck tractor, was gaining in popularity. In a semitrailer the truck tractor usually has a disk, known popularly as a fifth wheel, located on a horizontal platform over its rear wheels; a pin located under the front of the trailer locks into this disk, thus attaching the trailer to the tractor and furnishing support for the front end of the trailer. A semitrailer can therefore quickly be detached from a tractor, so that the tractor can be used to haul a second semitrailer at the same time that the first is being unloaded. All early trucks were powered by either steam engines or internal-combustion engines. The first tractors powered by diesel engines were built in the early 1930s. Diesel engines burned fuel oil instead of gasoline and ranged in power from 125 to 500 hp. Following World War II the diesel gradually became accepted in most heavy trucks and in some smaller trucks as well. The first modern tilt-cab, or cab-over, truck was built in 1935; in this truck type, the cab is placed over the engine and can be tilted up and forward to gain access to the engine. This allows a great savings in the length of the tractor, so that trailers can be longer and hence carry larger payloads. Trucks were used extensively by the military during World War I, which gave a major boost to the trucking industry. The U.S. Army had a fleet of 2,400 trucks in 1917 and added another 230,000 vehicles in 1918. Trucks also made a major contribution to the transportation of supplies during World War II. In the late 1920s and early 1930s the trucking industry, which was dominated by large numbers of itinerant owner-operators, was considered by many to be unstable, chaotic, and in need of economic regulation. The National Industrial Recovery Act (NRA) of 1933 brought together two organized groups of trucking officials to develop a code of fair competition and led to the formation of the American Trucking Associations. The organization submitted its code to the NRA in 1934. Every for-hire carrier was required to observe maximum hours of labor and minimum wages for all employees. The Motor Carrier Act of 1935 provided for safety regulation of interstate carriers, as well as economic regulation of for-hire carriers under the authority of the Interstate Commerce Commission (ICC). REGULATION AND DEREGULATION Under ICC regulation, operators with for-hire trucks who wished to carry freight into interstate markets had to apply to the ICC for a license to do so. Licenses were granted only if the need for additional truck capacity could be proved, and permission often also included the obligation to serve less profitable markets within the license region. In addition, the types of freight that could be carried by any one ICC-licensed truck were limited, with some commodities--such as food--under severe regulatory restrictions. Exemptions from ICC regulation were extended only to certain independent owner-operators, farmer cooperative truckers, and private carriers serving only their parent companies. The setting of trucking rates, which had been a matter between the individual trucker and the customer, gave way to the establishment of rate bureaus, which are owned and supported by all participating carriers. The bureaus researched and analyzed costs in order to establish competitive rates for the industry. Such an arrangement was made possible by a Justice Department antitrust exemption giving regulated trucking firms the power to collectively set rates subject to approval by the ICC. In 1980, however, Congress passed a trucking deregulation bill in the hope of increasing competition within the industry--and therefore saving consumers about $5 billion annually by reducing shipping costs. By removing many of the ICC regulations, the bill made entrance into the industry easier for new trucking firms, gave individual truckers greater rate-setting powers, and ended some types of collective rate making. It loosened ICC powers over route setting and over the categories of commodities that may be hauled by individual trucking firms, particularly easing restrictions on food hauling. Since deregulation the ICC has granted licenses to about 3,000 new carriers and approved 35,000 requests for expansion of routes--a vast increase over its approvals before deregulation. The large, established carriers find deregulation cutting into their business; smaller truckers and most shippers, however, generally approve lessened ICC control. Its effects on consumer costs are still undetermined. European countries differ in their approaches to regulating the trucking industry. Great Britain, for example, has largely eschewed regulation, whereas the Netherlands partially regulates trucking, and West Germany has full regulation of the type practiced in the United States before 1980. Truck weight and size limits on interstate highways have traditionally been regulated by the states. In 1983, however, the federal government enacted legislation that established the limits on interstate highways and on thousands of miles of local highways that serve as access to interstates or to major trucking terminals. The new law, which was challenged in court by several states, permits double-trailer trucks measuring up to 19.9 m (65 ft) in length, excluding cabs, to travel the nation's highways. The maximum width is 2.6 m (102 in), and the maximum weight, 36,287 kg (80,000 lb). In addition to increasing the weight and size limits of the trucks, the new law increased the national gasoline tax and various fees imposed on the trucking industry. The increased revenue was earmarked for construction and repair of highways. Trucks pay about 50% of all federal and state road user taxes. TYPES Today's truck is the result of engineering and technological advances of the 20th century, with economy, environmental impact, safety, and driver comfort as much a part of design as the load factor. A number of special types of trucks are built to perform specific functions. The pickup truck has a carrying capacity of 0.5 to 5 U.S. tons. Smaller types usually have a conventional design, whereas larger sizes have the cab situated over the engine. The loading area is designed for the particular job to be performed. It may have a flat bed, open bed, stake body, or closed van. The panel truck is a completely enclosed van having a capacity of about 0.5 U.S. tons. The straight truck may have a conventional or cab-over-engine design. The body length is designed for the job function. Where double- and triple-trailers are used, the straight truck may be used as the tractor, with the trailer or trailers coupled behind. The tractor may have a conventional or cab-over-engine design. It has a so-called fifth wheel and may have rear dual wheels mounted on a single axle, or tandem axles, depending on the usage. The semitrailer is a vehicle designed to be pulled by a tractor. It has either single or tandem axles on the rear. A steel plate with a welded or molded pin that is located on the bottom front slips and locks into the fifth wheel of the tractor. A "semi" may be an open flatbed, stake body, or fully enclosed van box. The full trailer is similar to the semitrailer except that it has front wheels as well as rear wheels and has a tongue for hooking it to a tractor or another trailer. A tandem unit consists of two trailers pulled behind a single tractor. They are generally not allowed on small or congested roads. Trucks that are even more specialized--for performing special and unusual jobs--include \Lfire engine\ls, refrigerated vans, mobile cranes, \Tearth-moving machinery\t, dump trucks, concrete mixers, garbage and trash trucks, and tank trucks for both dryand liquid-bulk hauling. PARTS AND SYSTEMS The basic difference between trucks and automobiles is that automobiles are people carriers whereas trucks are freight haulers; thus, each has its own characteristics geared to what is required. Trucks are larger, the ultimate limiting factor being the length, width, and weight permitted on the highways. Some trucks used exclusively in off-highway work, such as open-pit mining and earth-moving construction, are huge vehicles capable of carrying more than 50 tons. Gasoline or diesel internal-combustion engines requiring electrical ignition systems are commonly used as power units, with the horsepower ranging from 35 in light pickup trucks and vans to 250-300 in line-haul (long-distance) tractors, and even higher in special equipment. Whereas fuel consumption in light trucks may be comparable to that of heavier automobiles, the large trucks obtain only an average of 13 km (8 mi) per gallon of fuel. With the introduction of the diesel engine to trucking and the availability of refined diesel fuel, operating efficiency was greatly improved. Transmissions and drive-axle assemblies for trucks are larger, tougher, and far more intricate than those in automobiles. Automatic transmissions are available for some smaller trucks. Larger trucks, however, have manual transmissions, often with from four to ten forward speeds. Except for the front steering wheels, which are single wheels, larger trucks and tractors usually utilize dual-wheels, often in tandem, allowing as many as five axles on a tractor semitrailer with 18 tires. On smaller pickup trucks, the brakes are hydraulic, like those used in automobiles. Larger trucks and tractors, however, are equipped with a sophisticated system of air brakes with a greater stopping ability. Special devices are also used to prevent jackknifing while braking. Steering systems for trucks often have a hydraulic power-assist unit to reduce the steering effort. Truck cabs are designed and built to be comfortable and to prevent fatigue. Line-haul trucks and tractors are usually air-conditioned, are equipped with radios, and have a driver's seat that adjusts to a number of positions. Some tractors used for long-distance runs have a sleeping compartment, allowing one driver to rest while another operates the vehicle. Because of the rapid increase in the price of fuel in recent years, much research has been conducted on improved fuel economy. Recent advances include aerodynamic drag reduction, demand-actuated fan drive systems, steel radial tires, synthetic lubricants, and engine and drive train modifications. Drag can be dramatically reduced by an air deflector. This device, which comes in various shapes, improves the streamlining by deflecting air over the top of the trailer. The new fan systems--used also in some automobiles--turn the fan on and off as needed, either by a temperature-sensing device or by a centrifugal clutch that disconnects the fan when the engine, and hence vehicle, speed is high enough to provide adequate cooling. Having the fan disconnected when not needed can save a considerable amount of energy. THE INDUSTRY TODAY In the late 1980s there were over 40 million trucks of all sizes registered in the United States. Only about one million were combination tractor-semitrailers, the standard vehicles used by the trucking industry. Compact pickups, station wagons on truck chassis, and minibuses represented the largest increase in numbers, as car owners discovered the advantages of owning small trucklike vehicles. Truck industry revenues totaled over $200 billion annually, the product of over 600 billion ton miles of freight carried. The industry employed about 8 million people, making it the largest private industrial employer. The Motor Vehicle Manufacturers Association projects the following for 1995: the demand for truck haulage will double; alternative forms of energy will be used by trucks; and line-haul trucks of 50 U. S. tons (45,360 kg/100,000 lb) will become standard. Wilbert M. Hite Bibliography: Boyle, David H., How to Succeed in Big-Time Trucking (1979); Button, K. J., and Pearman, A. D., The Economics of Urban Freight Transport (1981); Childs, W. R., Trucking and the Public Interest (1985); Educational Research Council of America, Truck Driver, rev. ed. (1976); Harper, Donald V., Trucking in America: Users, Carriers, Government (1978); J.J. Keller, and Assoc., Inc., Federal Motor Carrier Safety Regulations Pocket Book, rev. ed. (1987); Jaskiewicz, L., and Kiley, E. J., Free Wheeling? A Reference for Economic Deregulation of the Motor Carrier Industry (1987); Loup-Nory, Jean, The Long Haul: Trucking in America (1980); Madsen, A., The Open Road (1982); Motor Vehicle Manufacturers Association of the United States, Motor Vehicle Facts and Figures (annual); Society of Automotive Engineers, Truck Safety (1986).