Determinants of EV adoption over time: Evidence from a Public Opinion Survey in Indiana

The transportation sector is the largest contributor to greenhouse gas emissions. Electric Vehicles (EVs) are viewed with great promise for addressing this global issue. While a large body of work focuses on EV adoption, the current literature does not differentiate the determinants of adoption over time. Distinguishing these determinants at different time frames is crucial for planning related strategies and policies. To address this research gap, this study investigates the factors that influence EV adoption and how their influence changes over time. A stated preference survey was conducted to examine the knowledge and experience of Indiana’s residents about EVs and charging stations. A total of 721 adults were considered in the study, all of whom had never owned or leased an EV. The sample was representative in terms of age, gender, and income for the Indiana population. The participants stated the likelihood to purchase an EV in the next 1, 2, 3, 5, and 8 years. A multivariate ordered probit was estimated to identify factors that influenced respondents stated intention to purchase an EV. The results revealed that respondents’ age, experience driving an EV, commuting distance, lack of knowledge of incentives (e.g., Federal Tax Credit and rebates to install home charges), lack of knowledge of charging technologies (e.g., Level 1, Level 2 and DC fast charging) as well as their political preference and pro-environmental behavior were determinants of EV adoption over time. All these variables were significant with a 90% or more confidence level in at least four of the five timeframes. The findings indicate that overall, older participants are less likely to purchase an EV. Respondents who have already driven an EV showed a higher likelihood of purchasing one. This trend remains constant across the different timeframes. Additionally, the effects of commuting distance and of lack of knowledge of available incentives changed over the years. In the first case, the impact was found to be more influential in the near than in the far-off future. The unawareness about EV incentives showed a negative impact that intensified over the years, which indicates that long-term educational campaigns to disseminate information about these incentives might have a positive impact on EV adoption. A negative and constant effect is observed among the participants who do not know about EV charging technologies. Finally, the interaction term between political preference and pro-environmental behavior was reported to be positively associated with EV adoption, an effect most pronounced in the long term. This can be attributed to the ideological aspect of these factors, with long-term actions driven by beliefs and short-term decisions tied to practical and economic considerations. Strong positive associations were found between the likelihood of purchasing an EV at different timeframes. This suggests people who show a stronger inclination towards adopting EVs within a year are also more inclined to contemplate EV adoption in the following year. This finding seems to suggest that short term strategies to accelerate EV adoption can also increase the possibility that EVs will be adopted in the long term too.