To begin, transportation economics covers a broad range of issues. There are differences between personal and freight transportation, among transportation modes, and between the fixed and variable parts of the transportation system. Analysis of personal transportation tends to focus on commuting and choice of mode, although there is also substantial interest in other personal transportation choices, such as time of day for travel and grouping of trips. For freight, the issues are primarily related to the cost of freight movement and the damage that heavy vehicles do to roads. Each mode has similarities and differences in the issues to be analyzed. For virtually all transportation systems, there is a large, typically publicly owned, infrastructure and a variable, often privately owned, set of ...