Automated shuttle buses (ASBs) hold significant potential for improving public transportation by enhancing urban mobility and sustainability. However, public trust in ASB and people’s intention to use them may depend on factors such as age and expectations of ASB behavior. This study examined how trust in ASBs’ capabilities influences the intention to use them and expectations of their braking behavior, specifically from the perspective of pedestrians and cyclists. Additionally, the study explored how age affects this relationship. Five hundred participants completed an online questionnaire assessing trust and behavioral intention to use ASBs. Participants then viewed video scenarios depicting ASBs interacting with pedestrians and cyclists and reported their expectations regarding the ASBs’ braking responses to prevent collisions. Structural equation modeling (SEM) revealed that trust positively predicted both the intention to use ASBs and expectations of their braking performance. Age was negatively associated with trust but did not predict intention to use or braking expectations. These findings show that trust is a critical factor in ASB adoption across age groups. To foster trust and encourage the adoption of ASBs, developers, providers, and policymakers, should prioritize delivering reliable, transparent, and user-friendly information and services that demonstrate ASBs’ safety and performance.