Abstract <p>Urbanization has intensified the demand for efficient passenger transportation systems, reinforcing the strategic role of public bus services in smart-city development. This study evaluates the operational efficiency of bus transport in 37 Brazilian municipalities (2022–2024) by applying a Simar–Wilson bootstrap data envelopment analysis with bias correction, integrated with beta and tobit regression models to points determinants of technical efficiency. The results indicated that no municipality achieved full efficiency, revealing substantial performance disparities: mean CRS efficiency was 0.597, mean VRS efficiency was 0.824, and mean scale efficiency was 0.712. The 22.7% gap between VRS and CRS scores highlights scale limitations as more restrictive than purely technical inefficiencies. Two clusters of municipal performance were identified. Controversially, municipalities adopting conventional best practices (such as user satisfaction surveys, origin–destination studies, and dedicated bus corridors) exhibited lower efficiency levels, in this case, suggesting these measures may be reactive responses to pre-existing system challenges rather than proactive drivers of performance improvement. São Paulo and Rio de Janeiro are exceptions, successfully combining such practices with relatively high efficiency. A leave out one robust analysis and a robustness analysis of the technical efficiency determinants were performed to cross-check the results. The findings underscore the necessity of context-sensitive, scale-appropriate policy design, demonstrating that the effectiveness of managerial practices may depend on institutional capacity and local conditions rather than their universal application.</p>