th the growing number of cars, there was a big demand for paved roads. During the 1920's Americans spent more than a $1 billion each year on the construction and maintenance of highways, and at least another $400 million annually for city streets26. But the automotive industry affected construction far more than that. The automobile had been central to the urbanization of the country in the 1920's because so many other industries relied upon it. With urbanization came the need to build many more apartment buildings, factories, offices, and stores. From 1919 to 1928 the construction industry grew by around $5 billion dollars, nearly 50%27.Also prospering during the 1920's were businesses dependent upon the radio business. Radio stations, electronic stores, and electricity companies all needed the radio to survive, and relied upon the constant growth of the radio market to expand and grow themselves. By 1930, 40% of American families had radios28. In 1926 major broadcasting companies started appearing, such as the National Broadcasting Company. The advertising industry was also becoming heavily reliant upon the radio both as a product to be advertised, and as a method of advertising.Several factors lead to the concentration of wealth and prosperity into the automotive and radio industries. First, during World War I both the automobile and the radio were significantly improved upon. Both had existed before, but radio had been mostly experimental. Due to the demands of the war, by 1920 automobiles, radios, and the parts necessary to build these things were being produced in large quantities; the work force in these industries had been formed and had become experienced.Manufacturing plants were already in place. The infrastructure existed for the automotive and radio industries to take off. Second, due to federal government's easing of credit, money was available to invest in these industries. Thanks to pressure from President Coolidge and t...
