Recent work in the private sector and current policy debates has refocused attention on Federal subsidies to passenger transportation modes. To provide the Department of Transportation with an independent analysis of this issue, BTS developed data on federal transportation revenues, expenditures, and net subsidies, by mode. We have also included discussions of cost allocation formulas with respect to federal trust funds, and of normalization metrics, both of which are important issues for such calculations. In addition we have discussed the role of social costs and benefits analysis of modal subsidies.