Primer on Motor Fuel Excise Taxes and the Role of Alternative Fuels and Energy Efficient Vehicles

Research output: NRELTechnical Report


Motor fuel taxes were established to finance our nation's transportation infrastructure, yet evolving economic, political, and technological influences are constraining this ability. At the federal level, the Highway Trust Fund (HTF), which is primarily funded by motor fuel taxes, has become increasingly dependent on general fund contributions and short-term reauthorizations to prevent insolvency. As a result, there are discussions at both the federal and state levels in which stakeholders are examining the future of motor fuel excise taxes as well as the role of electric and alternative fuel vehicles in that future. In 2015 alone, five states began to implement increases in their motor fuel tax rates. The current state of transportation infrastructure funding has placed the policies of vehicle efficiency and petroleum use reduction at direct odds with those promoting robust transportation infrastructure. The increase in federal fuel efficiency standards for vehicle model years 2017 through 2025 is projected to provide a benefit to the U.S. economy of between $372 and $507 billion by 2025 (NHTSA 2012), but fuel tax revenues are projected to decrease by $57 billion by 2022 (Dinan and Austin 2012). Additionally, the current method of calculating fuel taxes is based on volumetric measures or rough equivalencies, which does not always account for the energy content of the fuel, and the related distance traveled, as a direct indicator of a vehicle's impact on infrastructure. This penalizes a number of alternative, non-petroleum fuels. Furthermore, the introduction of plug-in electric vehicles into the consumer market (along with the option to charge at home, thereby largely avoiding fuel taxes) is directly cutting into transportation revenues. Accordingly, emerging technology raises important questions about collection mechanisms for motor fuel excise taxes. Decisions are being made or considered that may ultimately favor energy, transportation, or environmental outcomes and it will be important for decision makers to understand inherent trade-offs. A number of states are looking at or have already implemented legislation that bases fuel taxation on the energy content of a fuel and/or have established fees to recover lost fuel revenues from alternative fuel and electric vehicles. These mechanisms, while limited in their ability to solve broader funding questions, can help to contribute to a greater tax parity among motor fuels and vehicle technologies. However, they can only do so if implemented in a way that balances a number of trade-offs. If implemented incorrectly, these mechanisms could have the unintended consequence of favoring certain fuels, vehicle technologies, and types of uses over others. Beyond traditional motor fuel taxes, states and provinces are implementing or piloting other innovative funding mechanisms. For example, Virginia replaced their fuel excise tax with an indexed sales tax, allowing for adjustments to account for inflation. In July 2015, Oregon began piloting a tax on miles traveled as an alternative metric for taxing infrastructure use. British Columbia has implemented a carbon tax on motor fuels under its greenhouse gas regime. The experiences of these states and provinces, among others, are increasing the number of tools and knowledge available to policymakers who hope to align their energy and environmental priorities with adequate highway funding.
Original languageAmerican English
Number of pages46
StatePublished - 2015

NREL Publication Number

  • NREL/TP-5400-60975


  • alternative fuel vehicles
  • alternative fuels
  • CAFE
  • Clean Cities
  • efficiency
  • emissions
  • fuel excise taxes
  • highway funding
  • motor fuel taxes
  • transportation
  • vehicle miles traveled


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