Trucking has become the predominant means of delivering all types of goods, accounting for four-fifths of all domestic freight value in the United States. Trucks in the late 1990s hauled 1.5 trillion ton-kilometers of freight annually (a ton-kilometer is the movement of one metric ton over the distance of one kilometer). All types of manufacturing are also dependent on trucking for deliveries of parts and for shipping finished goods.
A trucking trade association estimates that about 9.7 million people in the United States are employed in trucking industry jobs, a figure that includes about 3.1 million professional truck drivers. In 2002 there were about 588,000 trucking companies in the United States. They generated over $580 billion in gross revenues.
At the beginning of the 21st century there were about 87.1 million trucks of all types on U.S. highways, out of a total of 217.6 million vehicles. The majority of trucks on the road were light trucks such as pickups and sport utility vehicles (SUVs); only about 21.3 million were trailers and semitrailers. In Canada, about 450,000 trucks are used to carry commercial freight.
Trucks that operate between states must be licensed in each state through which they travel, and their owners must pay road fees in each state. Trucks may be licensed to over-the-road commercial carriers, private delivery companies that operate their own trucks, or private owner-operators. Trailers are licensed separately from tractors and may be owned separately by a different company or fleet. There are about 4.7 million commercial semitrailers in the United States.
Drivers of over-the-road trucks must have a commercial driverís license, which is obtained by special training and the passing of written and driving examinations. Drivers must also keep written logbooks of their hours and miles traveled, as these are regulated for safety purposes to minimize driver fatigue. Drivers who work for trucking companies are generally paid by the mile, while owner-operators and commercial carriers charge for freight by weight and distance. A typical commercial over-the-road truck is driven over 161,000 km (100,000 mi) a year.
Trucking operations are regulated by state and local agencies to ensure safety on the road. Trucks traveling on interstate highways and primary roads must be inspected at weigh stations to make sure they are not overloaded. Drivers are fined if the weight exceeds the limit allowed for each axle. Trucks are also subject to safety inspections and may be put out of service if the brakes, tires, or other safety equipment do not meet standards. Because big trucks are so large and heavy, they cannot stop or maneuver as quickly as cars and light trucks can. Of the almost 42,400 traffic fatalities that occurred in the United States in 2000, about 12 percent involved heavy trucks. In most car-truck accidents, the truck driver often is uninjured or suffers only minor injuries because of the size difference between the vehicles.