Within the previous decade, many cities in Russia have introduced major changes in urban passenger transportation (UPT) systems with the aim to increase service quality and make public transport more attractive. The paper develops and tests a new user-oriented approach to UPT service quality measurement. The study is based on user-oriented approaches on service quality borrowed from the marketing field. The proposed approach combines qualitative and quantitative research methods. The data for analysis were collected in May 2024 through three focus groups (21 participants) and an online survey (398 respondents). Contrary to the bulk of literature on this issue, the current study focuses on subjective preferences of the users, where 24 service quality attributes are elicited through the focus groups while their importance and individual levels of satisfaction are measured through the survey. The use of subjective characteristics allows developing a UPT service quality index that can be utilised for longitudinal analysis and comparative studies. Testing of the proposed approach for the transport system of Saint Petersburg (Russia) showed that prioritised development areas for the UPT service quality increase are waiting time and conditions, traffic safety, predictability, transfer conditions, and ride smoothness. The study contributes to the understanding and measurement of UPT service quality and provides a tool for effective decision-making in urban transport system development.