The transportation policy of a government constrained by libertarian principles would aim to establish the institutional framework that would enable private entities to supply all the services that transportation users would be prepared to pay for, taking into account characteristics such as safety, frequency, and comfort. In some circumstances, government might have to assist in the provision of the services that users were not prepared to pay for—for example, roads that were specifically needed for national defense but have little other use—but these exceptions are almost certainly rare.

The movement of people and goods is critically important to interaction among individuals and to the development of social and commercial activities. It can take place on land, on water, and in the air. People have a propensity ...