Electric Buses and the Green Halo Effect on Transit Use

The electrification of urban bus fleets is an important strategy for reducing transport-related emissions and improving the sustainability of public transport (PT). Beyond its environmental benefits, however, the introduction of electric buses may influence passengers’ perceptions, satisfaction and willingness to use public transport. This research examines the relationship between bus electrification and public transport usage-related behaviour, focusing on the role of the Green Halo Effect (GHE), whereby the environmental characteristics of electric buses generate positive perceptions of the wider transport service. 

The study investigates the deployment of battery electric buses (BEBs) in Thessaloniki, Greece, where 110 electric buses were introduced in May 2024. An extended Theory of Planned Behavior (TPB) framework was developed, incorporating Green Self-Identity (GSI), attitudes, subjective norms, electric bus comfort attributes, satisfaction and the GHE. Two separate behavioural models were examined to distinguish between existing electric bus users and non-users. 

Data were collected through an online survey conducted between February and March 2026, involving 474 respondents, including 323 electric bus users and 151 non-users. Structural Equation Modeling (SEM) was applied to investigate associations between psychological constructs and behavioural outcomes. Necessary Condition Analysis (NCA) complemented the analysis by identifying factors that may limit the achievement of higher satisfaction or adoption intentions. 

For existing users, perceived physical comfort was strongly associated with satisfaction, while the GHE, general attitudes and satisfaction were positively associated with the model’s self-reported change-in-usage construct. The NCA identified physical comfort as an important necessary condition for high satisfaction. Among non-users, the GHE emerged as the strongest model-based predictor of future public transport usage intentions and a substantial limiting factor within the surveyed sample. 

The findings suggest that bus electrification may influence public transport attractiveness through two complementary dimensions: improvements in the perceived travelling experience and positive psychological associations with environmentally friendly technology. The research provides insights for transport authorities and operators seeking to understand passenger responses to fleet modernisation. However, the cross-sectional survey design does not establish causality or verify increases in ridership, and the non-user findings remain exploratory.

Supporting evidence

The research is based on 474 valid questionnaire responses collected in Thessaloniki during February–March 2026. Respondents were divided into electric bus users (N=323; 68.1%) and non-users (N=151; 31.9%). The questionnaire measured environmental identity, attitudes, subjective norms, perceptions of electric buses and usage-related outcomes using five-point Likert scales.

For existing users, SEM identified a strong positive association between perceived electric bus comfort attributes and satisfaction (β=0.895, p<0.001). The Green Halo Effect was also positively associated with the change-in-usage construct (β=0.411, p<0.001), alongside general attitude (β=0.482, p<0.001) and satisfaction (β=0.214, p=0.008).

NCA identified physical comfort as a substantial necessary condition for high satisfaction (d=0.462). For the change-in-usage construct, the Green Halo Effect had the largest necessity effect (d=0.238), followed by attitude (d=0.220) and satisfaction (d=0.127).

For non-users, the Green Halo Effect was the strongest predictor of intended public transport usage (β=0.961, p<0.001), while attitude and subjective norms were not statistically significant direct predictors. NCA identified a substantial limiting-factor pattern for the Green Halo Effect (d=0.490).

These findings reflect statistical relationships within a self-selected, cross-sectional survey rather than independently observed changes in ridership.

Key findings

1. Bus electrification may enhance public transport attractiveness beyond its environmental benefits. The findings suggest that the introduction of electric buses is associated with more favourable perceptions of public transport. The Green Halo Effect captures how environmentally friendly technology may positively influence perceptions of the broader service, potentially contributing to increased willingness to use public transport.
2. Physical ride comfort is particularly important for existing passengers. Among electric bus users, perceived comfort attributes, including reduced noise, smoother vehicle movement and comfortable interiors, were strongly associated with satisfaction (β=0.895). Necessary Condition Analysis identified physical comfort as a substantial limiting factor for achieving high satisfaction (d=0.462). Fleet modernisation should therefore be considered alongside the maintenance of satisfactory onboard conditions.
3. Psychological perceptions are associated with usage-related responses among existing users. The Green Halo Effect (β=0.411), general attitudes (β=0.482) and satisfaction (β=0.214) were positively associated with the model’s change-in-usage construct. These findings indicate that both experiential and psychological characteristics may be relevant to public transport engagement. However, the analysis does not establish objectively measured increases in passenger frequency.
4. The Green Halo Effect is especially relevant to the intentions of non-users. Within the exploratory non-user model, the Green Halo Effect emerged as the strongest predictor of future usage intentions (β=0.961). Its NCA effect size (d=0.490) also indicated a substantial limiting-factor pattern. General attitudes and subjective norms were not statistically significant direct predictors in this model. Given the smaller sample, these findings require further validation.
5. Fleet electrification offers opportunities for further behavioural research and policy experimentation. Public transport authorities could test whether communication strategies highlighting electric buses’ environmental and technological characteristics improve perceptions among potential passengers. Operators could also investigate how maintaining ride comfort supports user satisfaction. Longitudinal studies and controlled field experiments are required to assess these possibilities, distinguish electrification effects from vehicle novelty and determine whether favourable perceptions translate into sustained ridership changes.