U.S. Cities are economic producers, primary profit-making centers, increasingly decentralized, have some public transportation, mostly private autos, have freeway systems and have relatively low land prices and energy prices. The arrival of the automobile after W.W.I turned America from compact cities to widely dispersed cities of the post W.W.II highway era. Millions of Americans, most of them urbanites, prefer to consider their country as a basically rural place, and they seem to believe that this rurality provides the country with a basic national vigor. There is no longer much justification for this view of rural dominance. About 70 percent of Americans live in urban areas, and more than 40 percent are in areas of 1 million people or more.
Cities exist for many different reasons.
They may have an important transportation role. Or they may provide an important administrative function. Perhaps they are a center of recreation or manufacturing. Most cities, certainly all large ones, contain many different urban functions. Nevertheless, many are characterized by certain dominant functions that were the reason for their development and much of their early growth, and that today continue to give them their special character.