TRANSPORTATION AND COMMUNICATION
It is five o'clock on a winter evening. The city's population pours forth from factory and warehouse, office building, and department store. Each person is intent upon one thing—the best way to get home. The streets are heavily laden: automobiles, buses, trams, and elevateds line up to transport anxious homegoers. Not far away, trains at railway terminals await suburban commuters; some few planes stand ready at airports to fly their passengers to neighboring cities. It is the peak hour of transportation, of traffic jams and accidents, of pushing and crowding.
The passenger's day of work is done. The vehicle's is not. The vehicle is an extension of the working world. It is made of steel from the steel mill, of wood from the lumber yard. It carries men and women, but it also carries freight. It moves building materials across the continent. It brings produce from the farm to the city, cotton from the plantation to the textile factory, coal from the mine to the mill. And in turn it distributes manufactured goods to markets and to ultimate consumers. The vehicle of transportation has evolved with the factory itself. It has been mechanized apace with industry and trade.
Economic Interdependence.The swift evolution of transportation and the rapid building up of its mechanical base have paralleled similar developments throughout the economic system. In fact, a close interrelationship exists in the growth of the many segments of the modern order. The production of steel, as an instance, may account for a great industrial center like Pittsburgh; but without the large demand for steel rails on the part of railroads, the city would