Nearly every product used in the country has been transported by a truck at some point -- it is the most efficient means of door-to-door product transportation available today.
The first semi-trailer appeared in 1881 and was towed by a DeDion steam tractor. The internal combustion engine followed in 1898, the invention of Germany's Gottlieb Daimler. By 1904, there were 700 heavy trucks on the roads in the United States. In 1912, the Knox-Martin three-wheeled tractor debuted and was the earliest representation of the modern tractor-trailer.
The trucking industry was not a major transportation provider until the 1930s; prior to World War I, people thought of trucks as noisy, awkward carts. Trucks in the United States relied on gasoline up until the 1970s, despite the invention of the diesel engine in 1890.
Truck drivers are typically paid by the mile and wages can vary considerably depending on distance, experience, and loading and unloading responsibilities.
Truck drivers are required to hold commercial drivers' licenses. A variety of programs offer training to earn those credentials.