The introduction of pneumatic tires and general road improvements in the 1920s stimulated the growth of trucking. In addition, truck companies began taking advantage of deficiencies in railroad service. During the 1930s limited industrial production, smaller inventories, and preference for restricted business operations combined to favor trucking. The decline in intercity motor trucking during World War II was due primarily to the difficulties in obtaining vehicles, gasoline, and tires. Government programs also discouraged the use of motor transportation during the war. After the war, however, motor trucking resumed its steady growth. Greater industrial productivity kept tonnage high. In the postwar period, technological advances, highway improvements and expansion, inadequacies and abandonment of railroad service, and general economic prosperity have worked to expand motor trucking.
In the United States all communities depend to some degree on intercity truck transportation, and more than half of them depend exclusively on trucking to supply their needs. The Eno Transportation Foundation reports that intercity trucks, both private and for-hire, in the United States carried 1,051 billion ton-miles (1,691 ton-km) in 1997, which was 29.1% of the nation's total. Locally, the truck is relied on almost exclusively, and it is a rare product that has not been carried by truck at some time. Standard & Poor estimates that for the year 1997, $372 billion was spent on truck freight (81.3% of the nation's freight bill) and intercity and local trucks transported 6.7 billion tons of freight (60% of the total domestic tonnage shipped).
According to the American Trucking Associations (ATA), 19.84 million trucks were used in 1997 for business purposes (excluding those used by government and the farming community) in the United States (25.7% of all trucks used for business and personal activity). The Federal Highway Administration reports for the same year that 1.97 million trucks were owned by government. Although the for-hire trucking industry is characterized by a large number of firms that are small in size, some fairly large U.S. firms exist. As of December 1998 the Department of Transportation's Federal Motor Carrier Safety Administration had 458,634 interstate motor carriers on file. According to the ATA 9.5 million people were employed in the United States in 1996 in jobs directly related to trucking (earning $282 billion in wages) and that nearly 3.1 million were employed as commercial truck drivers in 1997.
In 1999, manufacturers produced 7,423,375 million trucks in the United States, nearly half of the world production total of 16,600,988 trucks. Other major truck producers were Japan (1,904,298), Canada (1,398,305), China (1,218,878), South Korea (518,004), Mexico (499,894), Spain (480,021), France (405,019), Germany (352,656), Italy (288,795), Brazil (253,766), Russia (228,000), the United Kingdom (180,802), India (138,393), South Africa (107,506), and Taiwan (105,290).
