Assessing the determinants of passenger satisfaction in public bus transport systems: A fuzzy approach

Context—Passenger satisfaction is a crucial factor in encouraging the use of public transportation over private vehicles, as it directly affects user loyalty, service effectiveness, and overall urban mobility. Assessing satisfaction in public transport systems is inherently challenging due to the subjective, multidimensional, and uncertain nature of passenger perceptions. The EN 13816 standard offers a comprehensive framework for evaluating public transport service quality through criteria such as accessibility, comfort, safety, security, availability, and information. Nevertheless, traditional evaluation approaches often face difficulties in integrating both qualitative and quantitative aspects of service quality while effectively managing uncertainty in passenger judgments. Therefore, identifying and analyzing the key factors influencing passenger satisfaction is essential for enhancing service performance, increasing ridership, and supporting sustainable transportation policies and urban development goals.Objective—This study aims to develop a robust framework for assessing passenger satisfaction in public transportation systems by integrating both passenger and operator perspectives. The objective is to identify, prioritize, and evaluate service quality criteria to support informed decision-making for service improvement. The study also seeks to highlight the gaps between passenger expectations and operator assessments, thereby providing actionable insights for transit management.Method—A hybrid two-level analytic hierarchy process (AHP) integrated with intuitionistic fuzzy sets was employed to address the uncertainty and complexity inherent in multi-criteria decision-making. The AHP method was used to determine the relative importance of service quality criteria, while Intuitionistic fuzzy sets were utilized to capture the vagueness and uncertainty in expert judgments. Transportation experts from diverse disciplines, including strategy development, operations management, and information technology, evaluated the criteria to provide a comprehensive assessment. The proposed framework was validated through a case study of Istanbul’s public bus transportation system. Additionally, gap and sensitivity analyses were conducted to examine the differences between passenger and operator perspectives and to evaluate the robustness of the model.Results—The analysis revealed that safety and security are the most influential factors for both passengers and operators. From the operator perspective, service availability is equally critical, whereas passengers rank availability second, followed by comfort and travel time. The gap analysis highlighted areas of consensus, such as accessibility, as well as significant differences in comfort and information criteria, indicating priority areas for improvement. The sensitivity analysis confirmed that the model is responsive to variations in expert judgments, emphasizing the importance of carefully selecting evaluators.Conclusion—The integrated AHP–Intuitionistic Fuzzy Sets framework provides a reliable and adaptable tool for evaluating passenger satisfaction in public transportation systems. By identifying key service quality criteria and highlighting gaps between passenger and operator perceptions, the proposed model supports targeted improvements in service planning and management. The findings provide practical guidance for transit operators to enhance passenger satisfaction, increase ridership, and contribute to the development of more sustainable urban mobility systems.