The National Academies

NCHRP 19-22 [Anticipated]

Future Equity Impacts of Existing Fuel Taxes

  Project Data
Source: AASHTO Committee on Funding and Finance
Funds: $450,000
Staff Responsibility: Camille Crichton-Sumners
Fiscal Year: 2023

This project has been tentatively selected and a project statement (request for proposals) is expected to be available on this website. The problem statement below will be the starting point for a panel of experts to develop the project statement.

The current fuel tax mechanism for funding surface transportation will likely remain in place for years to come, despite some movement toward future implementation of a mileage-based fee. As a fixed per-gallon fee, the federal fuel tax represents a larger share of income the less a payer makes. This research will explore how this disparity may widen as the vehicle fleet becomes increasingly fuel-efficient and alternative fuel vehicle ownership increases, including electric vehicles.


Improvements in vehicle fuel efficiency are developing at a rapid pace. Auto manufacturers are expanding production of electric vehicle models and states have set ambitious goals for new electric vehicle ownership. Meanwhile, lower income drivers tend to replace their vehicles less frequently and will continue driving less fuel-efficient vehicles. The equity disparity around what proportion of an individual’s income contributes to fuel costs will continue to grow under the current fuel tax structure. This research relates to AASHTO’s strategic goal of advancing equity in transportation, and will benefit state departments of transportation (DOTs) that depend on fuel tax revenue forecasting to allocate resources and make spending decisions.


The objectives of this research are to quantify the long-term user equity impacts of the current fuel tax mechanism in order to aid state DOTs in revenue forecasting; perform a detailed economic analysis of vehicle manufacturing and purchasing trends of new and used vehicles over the next several decades and the resulting equity impacts; identify obstacles for low-income users to access plug-in vehicle infrastructure; explore vehicle use trends for low-income users; and develop a revenue forecasting methodology that incorporates these elements.

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