Long haul trucking has evolved significantly over the decades. Here’s two films from about 1950 or so that show how it was done at a time when it was a regulated industry, dominated by a few common carrier companies like Pacific Intermountain Express, the subject of this first film, West Coast, the subject of the second, and Consolidated Freightways.
Common carriers’ rates were fully regulated, as were the freight railroads back then, and the operations are a bit similar. These companies were vertically integrated, with their own shops where all service was carried out, including a complete overhaul of each tractor every 450,000 miles (about two years), including new paint.
The second set of films are on West Coast, another big firm covering the Western states. There’s more over-the-road footage, on several routes.