Understanding changes in electric vehicle policies in the US states, 2010-2018

State-level policy support for electric vehicles (EVs) increased from 2010 to 2015. A total of 27 U.S. states enacted a variety of subsidies to promote EV adoption and use. From 2015, however, many states repealed their policies and others levied annual EV fees. There is a lack of coherence in state approaches to EV policy, most exemplified by states that both subsidize EV purchases and charge them annual fees. Using panel data on EV purchase subsidies, home charger subsidies, and annual EV fees from 2010 to 2018, we estimate whether changes in economic, environmental, demographic, political, and ideological factors explain variation in state EV pol-icies. We find that environmental ideology and state politics are the main factors supporting state EV subsidies. Economic and environmental pollution factors only played an important role in enactment of annual EV fees, as states with higher unemployment, lower reliance on the gas tax, and better air quality are less likely to impose annual EV fees.