In this research, models primarily based on the Highway Economic Requirements System (HERS) are retrofitted to calculate six component marginal costs: Safety, Travel Time, Vehicle Operations, Agency, Emissions, and Noise. Each of these marginal costs is separately obtained for both peak and off-peak periods for seven different vehicle types. By combining these component costs, the true marginal cost to society of each vehicle is obtained for each roadway segment reported in the Highway Performance Monitoring System. This full marginal cost can be applied in future policy analysis in defining appropriate vehicle miles traveled (VMT) fee structures.

In addition to calculating segment marginal costs, this report conducts a section level revenue analysis that compares the revenue generated by the current gas tax system employed by the United States versus a revenue system based on vehicle mile fees developed from marginal vehicle cost analyses.