Previous assessments of the full costs of transportation have identified three types of costs: public, private, and external (Anderson & McCullough, 2000; Delucchi, 1996). For public and private costs, analysts distinguish capital costs from on-going operation and maintenance expenses. For example, Anderson and McCullough’s 2000 inventory of public capital costs for the Minneapolis-St. Paul regional light rail system included the cost of land acquisition along the rail corridor and the light rail cars used for the light rail system.  In a similar full cost analysis study, Delucchi and Murphy (1998) included the cost of acquiring land to build off-street parking in their transportation system cost evaluation in the United States.  This section reviews the cost categories used in other public, non-school transportation system evaluations in order to consider school travel cost elements that would be relevant and necessary for a full cost inventory.


The public costs of transportation systems include capital costs and the ongoing costs of operating and maintaining a transportation system for government agencies. For example, public capital costs may include the marginal or total cost of land required for a project, road and highway construction associated with material and labor, off-street parking facility construction costs, and the costs of acquiring transportation system components, such as buses and light rail cars. Examples of public operating and maintenance expenses include road pavement repair and maintenance costs, the labor costs of collecting highway user fees, the cost of subsidies to transit service, parking attendant salary and benefits, the salary and benefits of transportation police, fire and emergency protection, and the cost of licensing drivers. Collectively, public capital and operating costs are substantial. In their cost estimation of the Minneapolis-St. Paul transportation system, Anderson and McCullough (2000) estimated that the annual cost of constructing and maintaining the Minneapolis-St. Paul street and highway system was between $1,340 and $1,735 million (1998 USD) and the cost of transit between $245 and $270 million (1998 USD) annually.


Private sector, or internal, costs represent expenditures by private citizens who are users of the transportation system. Private expenditures include out-of-pocket expenditures on vehicle ownership, maintenance, insurances, fuel, and other similar costs, but also include the value of personal travel time. The inclusion of in-vehicle travel time (IVTT) in the evaluation of transportation project proposals can improve the accuracy of total transportation system cost estimates (Wardman, 2012). Meta-analyses reviewing IVT estimates suggest that longer commuting trips are more costly than comparable shorter trips for leisure (Shires & De Jong, 2009; Wardman, 1998). In their evaluation of the Minneapolis-St. Paul transportation system, Anderson and McCullough (2000) included monetary estimates for the value of commuting time travel using hourly wage estimates for the Minneapolis region. These hourly wage rates were then discounted based on trip type (i.e. commuting) and applied to IVTT estimates for drivers in the transportation system. In addition to the value of in-vehicle travel time and vehicle maintenance, Anderson and McCullough included the internal costs of residential parking provision and personal costs of traffic crashes in their private user cost estimates.


External costs include the impacts of transportation that are not reflected in direct costs to the public or private sectors.  For example, road congestion imposes costs on public traffic service provision and management (Litman, 2007).  Further, emissions associated with transportation have impacts on local air quality, public health, and the world’s climate that are unpriced in budgetary cost models (Delucchi, 1996).  In the Minneapolis-St. Paul example, Anderson and McCullough (2000) identified six external cost categories: traffic congestion; air pollution (decomposed to health and non-health related); traffic crashes; noise pollution; petroleum-related incidents (i.e. robbery and fire); and community impacts of transportation projects.  With respect to the cost of these externalities in Minneapolis, traffic congestion was projected to cost between $165 and $560 Million (1998 USD); traffic crashes between $150 and $320 Million; air pollution between $385 and $4,585 Million; noise pollution between $5 and $29 Million; and fire and crime between $11 and $47 million per year (Anderson & McCullough, 2000).