The operation of automated buses (ABs) as a feeder transport service has been advocated as one of the most suitable ways to integrate shared automated vehicles into the current public transportation system. Previous studies based on pilot demonstrations have explored public attitudes and perceptions toward ABs, but most of those studies have relied on cross-sectional data, which cannot capture changes in attitudes over time. To address this gap, a one-year, three-wave panel survey was conducted in Stockholm, Sweden, with a focus on passengers’ real-world experiences in relation to an automated bus operating in mixed traffic on public roads. Latent curve analysis was applied to the longitudinal data to examine the evolution of service evaluations. Although the findings indicated that passengers initially rated speed and travel time unsatisfactorily, these evaluations showed steady improvement over time. In contrast, perceptions of safety, comfort, and convenience were positive at the outset but underwent a moderate decline throughout the study period. Current public transport users and tech-savvy individuals were identified as the primary user groups most likely to adopt ABs in the future.