Mobility-as-a-Service for Sustainable Transportation: A Bibliometric and Thematic Review

Mobility as a Service (MaaS) has emerged as a transformative paradigm in urban transport, aiming to integrate diverse mobility modes into unified, user-centric, and digitally enabled platforms. Despite rapid growth in academic interest, the MaaS literature remains fragmented both thematically and methodologically, with key questions concerning intellectual structure, geographic representation, and governance implications remaining inadequately addressed. This study maps the evolution of MaaS scholarship through an integrated dual-method framework combining quantitative bibliometric analysis with qualitative thematic synthesis, applied to 396 peer-reviewed publications indexed in Scopus between 2016 and 2024. The analysis reveals an annual growth rate of 34.69%, a pronounced concentration of research in Global North institutions, and five dominant thematic clusters: user behavior and adoption, governance and institutional frameworks, sustainability and equity, digital platforms and infrastructure, and algorithmic optimization. The bibliographic coupling and keyword co-occurrence networks further indicate that these clusters operate in relative isolation, with inter-cluster integration remaining underdeveloped relative to the systemic complexity of MaaS. Persistent knowledge gaps include longitudinal behavioral evaluation, Global South research representation, data governance frameworks, and the policy conditions required for equitable MaaS deployment. The study contributes a structured and evidence-based future research agenda, a policy implications framework for urban mobility governance organized around five dimensions, governance integration, data governance and interoperability, equity and inclusion, sustainability performance evaluation, and public-private value allocation, and an analytically integrative reference for scholars and policymakers navigating the next phase of MaaS development.