Transportation is an economic function serving along with other productive functions in the production of goods and services in the economy. If we can define production as the creation of utility, i.e. the quality of usefulness, then transportation creates the utility of place and time. That is to say goods may have little or no usefulness in one location at one time but may have great utility in another location at another time. One, naturally, has to bear in mind that some goods are so common as to be present almost everywhere and little can be gained by transporting them. Other goods may be unique and valuable so that they can be profitably transported great distances. Nevertheless as economic policies change, market barriers disappear and transportation costs reduce, even in the former case the benefits of transportation may outweigh the costs of producing locally.