The causal relation between off-street parking and electric vehicle adoption in Scotland

Abstract

The transition to electric mobility depends on widespread adoption and equitable access. We examine whether the “charging divide” between households with and without off-street parking reflects a true infrastructure constraint or underlying socio-economic disparities. We apply a probabilistic graphical model to nationally representative Scottish household data to identify the causal effects of parking access and income on electric vehicles (EV) adoption. Results reveal that access to private off-street parking increases EV ownership probability from 3.3% to 5.6%, an estimated causal effect of +2.3 percentage points (70% relative increase). The (1st; 99th) percentile bootstrap interval is + 0.26 ; + 4.77 percentage points, while the corresponding basic bootstrap interval is − 0.17 ; + 4.34 percentage points. The effect primarily operates by increasing conversion among households already intending to adopt, rather than expanding the pool of households considering adoption. In contrast, income is identified as the primary barrier to market entry, with higher-income households showing a 23.1 percentage point lower probability of no intention to purchase EVs compared to lower-income households. Models optimised for predicting observational outcomes overstate the effect of parking by conflating correlation with causation due to confounding bias, specifically by inflating its impact among households with no intention to adopt an EV.

The authors' abstract, as published at the source. Transportation Research Part A Policy and Practice, 2026 · DOI ↗