From policy to reality: Forecasting Spain's vehicle fleet trajectory toward 2030 climate targets

Abstract

This study assesses the trajectory of Spain's vehicle fleet by propulsion type to evaluate the feasibility of meeting national and European decarbonization targets for 2030. Using disaggregated microdata from the Spanish Directorate-General for Traffic (DGT), five time-series models (SARIMA, ETS, Harmonic regression, NNAR, and STLM) are applied to monthly registration data from 2014 to 2025 to generate projections up to 2030. The forecasting results indicate that, although electric vehicle (EV) adoption is increasing, current trajectories remain insufficient to achieve the targets established in the National Integrated Energy and Climate Plan (PNIEC). While gasoline and diesel vehicles show stagnation or decline, EVs follow a sustained but moderate growth path that falls short of the required expansion. To complement the forecasting analysis, the study incorporates an exploratory econometric approach to examine the relationship between EV adoption and key policy and market drivers. The results show that EV adoption is strongly associated with macroeconomic conditions and exhibits significant persistence, while fuel prices do not appear to play a statistically significant role. Policy interventions have a positive but not fully robust effect across specifications. In addition, a bidirectional relationship between EV adoption and charging infrastructure is identified, suggesting a process of co-evolution. Overall, the findings indicate that the transition to electromobility in Spain is progressing but remains insufficient to meet policy targets under current conditions.