The trucking industry in the United States and Canada has affected the political and economic history of the United States and Canada in the 20th century. Before the invention of automobiles, most freight was moved by train or horse-drawn vehicle. Trucks were first used extensively by the military during World War I. With the increased construction of paved roads, trucking began to achieve signifi
cant foothold in the 1930s, and soon became subject to various government regulations (such as the hours of service). During the late 1950s and 1960s, trucking was accelerated by the construction of the Interstate Highway System, an extensive network of freeways linking major cities across the continent. Trucking achieved national attention during the 1960s and 70s, when songs and movies about truck driving were major hits. Truck drivers participated in widespread strikes against the rising cost of fuel, during the energy crises of 1973 and 1979, and the industry was drastically deregulated by the Motor Carrier Act of 1980. Trucking has come to dominate the freight industry in the latter portion of the 20th Century, along with what are termed "big-box stores" such as Wal-Mart and Target.