The Intention–Adoption Gap in Public Transport Use Among Car-Dependent Commuters

Understanding the gap between individuals’ intention to reduce car use and their actual willingness to adopt public transport is critical for advancing sustainable urban mobility. This case study in Rome examines how perceived public transport service quality and travel burden influence car-dependent employees’ willingness to shift to public transport. The analysis draws on survey data collected from 392 respondents, including 190 car-dependent employees, between May and July 2024. The results reveal that perceived public transport service quality has a significant positive direct effect on willingness to use public transport. In contrast, its indirect effect through intention to reduce car use is not significant. In contrast, travel burden does not show a significant total effect on willingness; however, in the combined model, it exhibits a positive direct effect on willingness, while its indirect pathway through intention is weak. Furthermore, travel burden has a marginal negative effect on intention, reflecting structural constraints associated with car dependency. Intention is a strong predictor of willingness but does not significantly mediate the effect of service quality. It also shows a significant interaction effect with travel burden in the combined model. Overall, the findings suggest that improving public transport service quality is more effective in encouraging modal shift than increasing the burden of car use. This highlights the importance of service-oriented and user-centered interventions, as well as the need to address structural barriers that limit behavioral change.