Assessing the Spatial Distributions of Public Electric Vehicle Charging Stations with Emphasis on Equity Considerations in King County, Washington

This study assessed the availability and accessibility of public electric vehicle (EV) charging stations at the census tract level in King County, Washington, USA. A gravity model was used to measure the accessibility of stations in each tract while considering the competition among tracts for charging infrastructure. Unlike prior studies, we evaluate current distribution from various equity viewpoints, clearly defining these perspectives and investigating their implications for charging distribution. The findings revealed significantly higher accessibility of public stations in areas with a lower share of single-family homes, a higher share of commercial areas, and proximity to major roadways, irrespective of population and EV adoption rates. Moreover, we found that the current distribution is consistent with utilitarian and capabilities-based theories of equity. Spatial tools such as Moran's I and spatial regression were used to analyze the spatial disparity of the proposed accessibility measure, showing the existence of a highly clustered spatial distribution. This study offers valuable insights into integrating equity considerations in assessing accessibility to transportation facilities, especially EV charging stations. Such an approach can facilitate the promotion of EV adoption across diverse groups, a critical factor in achieving sustainable city development goals by mitigating carbon emissions and enhancing mobility.