Policies can accelerate EV diffusion by enhancing consumer expectations of future prevalence

The early stages of electric vehicle (EV) adoption face a classic chicken-and-egg dilemma: EVs are inconvenient without sufficient public chargers, while installing chargers is unprofitable with too few EVs. Government policies may help break this cycle by fostering optimistic expectations about future EV diffusion. We conducted a randomized controlled pre-post survey experiment with 500 Tokyo residents, where only treatment groups received information about the city’s zero-emission vehicle (ZEV) sales target and a new EV-ready building code requiring charger installation in new apartment complexes. Results show that exposure to this policy information increased participants’ willingness to purchase a ZEV—even among those not directly affected by the policies. Mediation analysis indicates the effect was driven by enhanced optimism about future ZEV adoption. These findings highlight the critical role of consumer expectations in shaping the effectiveness of EV policies and underscore the value of broadly communicating policy initiatives to accelerate EV adoption.