Transportation Taxes and Energy Transitions: Alternative Policy Designs for Funding US Road Infrastructure and Pricing Externalities

Federal and state tax policies designed to fund the construction and maintenance of transportation infrastructure rely almost exclusively on excise taxes levied on petroleum products. But as the United States and the world seek to reduce greenhouse gas emissions, boosting fuel economy and electric vehicle (EV) sales will reduce the demand for petroleum and associated public revenues. In this analysis, we use an economic model of the US household vehicle market to estimate the effects of three alternative revenue policies: one that adjusts tax rates for internal combustion engine (ICE) vehicles and adds a new per-mile fee for EVs to maintain the performance of US roadways, a second that levies a per-mile fee on all vehicles in lieu of the gasoline tax, and a third that charges all motorists for the external costs of driving, including greenhouse gas emissions, “local” air pollution, traffic accidents, and congestion. We also examine the effects of extending fuel economy standards beyond their current levels. We find that current tax policies are insufficient by tens of billions of dollars per year to fund roadways and that either higher taxes on gasoline or a per-mile fee of $0.03 levied on all passenger vehicles could achieve the target revenue. Tightening fuel economy standards lowers the cost of operating ICE vehicles and reduces tax revenues. Imposing a per-mile fee on EV owners has virtually no effect on EV adoption because of interactions with other policies but does slightly reduce EV miles driven. We produce an updated estimate of the external costs of driving, averaging $0.16 per mile for gasoline vehicles ($3.85 per gallon) and $0.06 per mile for EVs, with large differences between urban and rural counties. Applying fees at this rate dramatically accelerates EV adoption, increases driving costs (especially for ICE vehicles), slightly reduces overall driving, and raises tax revenues well beyond the level needed to maintain roadway performance.