The advent of automobiles changed the lives of Americans more than we can imagine. More than 20 million drivers who owned a car in the 1930s actually boosted the growth of steel and oil industries essential to automobile construction. Plenty of other industries benefited from the spread of automobiles as well. The infrastructure developed fast and motels were actively constructed along the roads, and taverns provided fast food that soon became traditional to the US.
The fast success of the automobile industry we owe to Henry Ford who spent years to design and start manufacturing of Model T. It was a low cost and reliable automobile targeted at those who could not afford to buy luxury items. Besides making it cheaper to own a car, Ford created plenty of workplaces, including those in related industries. The infrastructure developed so fast that unemployment shrank fast.