Disparities in electric vehicle charging infrastructure distribution: A socio-spatial clustering study in King County, Washington

Abstract

Transportation electrification has emerged as a critical strategy for mitigating greenhouse gas emissions, yet recent studies have indicated multifaceted injustices in adopting electric vehicles (EVs). One key issue is the equitable planning of public electric vehicle charging infrastructure (EVCI), which is essential for promoting widespread EV use. While existing research predominantly focuses on measuring accessibility, limited attention has been given to equity assessment based on urban social typologies. This study examined EVCI distribution in King County, Washington, using a three-step framework: First, we clustered six micro-urban typologies incorporating 17 socio-spatial indicators. Second, we measured and mapped charging capacity standardized rates across the county. Third, we identified key factors, examined how their influence varies geographically, and analyzed disparities by comparing specific clusters. Our findings show that the current distribution of charging stations is capacity-driven, favoring en-route recharging needs over longer-stay residential charging needs. This trend disproportionately affects underserved communities in southern King County, leaving large residential areas underinvested. This utilitarian distribution potentially exacerbates the inequalities in the EV adoption process. Therefore, future EVCI planning needs to prioritize residential charging access, and community-level charger expansion should consider neighborhood-specific needs and readiness. Importantly, our proposed assessment framework can be applied to support nationwide transportation electrification efforts.