By 1972 there were nearly one million tractor-trailer rigs hauling every conceivable kind of cargo on America's roads. Can you imagine the variety of trucks you would have seen at truck stops across the country? But the 1970s proved to be a decade of incredible change for the over-the-road trucking industry, and by 1980 fuel efficiency became a prime concern for companies. At this time, airfoils and other aerodynamic aids began to appear and trucks in general started to take on a similar look. In this picture-packed book, Ron Adams has pulled together a collection of over 300 images that traces the evolution of truck design and use back to the earliest horse-drawn units right up through the early 1980s. Short introductory chapters cover the earlier years of trucking and then Ron takes you on a coast-to-coast tour of the 1970s, showcasing the huge variety of big rigs working the roads and providing detailed information about the trucks, trailers, cargoes, and trucking companies. In addition to photos and detailed captions, there are period articles covering early aerodynamic testing and also on advancements in truck design in the 1970s. Semi Trucks of the 1970s features trucks from all makers, including International, Freightliner, Kenworth, Mack, White-Freightliner, Autocar, Brockway, Peterbilt, Ford, and Diamond Reo. This is a complete look at this evolutionary period in trucking history.