<p>This study examines how municipal governments evaluate the effectiveness of public services, with a particular focus on public transportation. A case study approach was adopted, drawing on multiple data sources, including semi-structured interviews with seven municipal government employees and two researchers, observations, and documentary analysis. The information obtained was then compared with data from two other Brazilian cities, which are regarded as benchmarks in the provision of public transportation. Data triangulation was undertaken to enhance the reliability and depth of the findings, enabling cross-verification of information obtained from different sources. The results reveal a gap in Brazil, as local governments rarely use performance indicators, indicating a disconnect between the recognized importance of performance measurement and its practical application. Based on the analysis, we propose a system for evaluating public transportation in the city of Minas Gerais. This system comprises 15 key quality indicators and a transport quality indicator, which measures overall service quality. These indicators enable the monitoring of aspects such as punctuality and adaptation for people with special needs, thereby benefiting users and improving both the quality and reliability of the service. Moreover, the implementation of certain actions within the system is recommended to manage the concession contract and ensure service quality. It is expected that this research will serve as a subsidy to assist the competent authority in evaluating and supervising the services provided, as well as to serve as a template for evaluating the quality of any municipal services. The use of performance measurement systems in public service contracting documents can be regarded as a municipal strategy for quality control, decision-making and enhancements, and ultimately, for meeting user demands.</p>