Monitoring and evaluation of travel behaviour change in mobility-as-a-service (MaaS) trials: Insights from a longitudinal study

Travel behaviour change towards more sustainable modes of transport is required to achieve environmental sustainability. Mobility as a Service (MaaS) trials have been implemented in various cities over the past decade to reduce private car usage, and promote sustainability. Monitoring and evaluation (M&E) is a key component in developing MaaS trials, as it enables a comprehensive understanding and analysis of the MaaS's impact on modal shift. Although the insights from various MaaS trials have been explored in the literature, studies on the travel behaviour change M&E of these trials with longitudinal approaches were lacking. This paper proposes a M&E approach employing the Differences-in-Differences (DiD) method and incorporating three Key Performance Indicators (KPIs), to monitor and evaluate the travel behaviour change after the launch of the MaaS app. It uses longitudinal (baseline and recall) data to analyse the impact of MaaS on travel behaviour change for its users compared to non-users. The application of the proposed DiD-based M&E framework has been tested and validated on a real-world MaaS project with 887 MaaS users and 757 non-MaaS users. The results suggest that the private car use is reduced while public transport use increased for MaaS users, while for the non-MaaS users, the private car use is increased and public transport is decreased. Moreover, the DiD analysis showed that the impact of MaaS on the decrease in the private car and increase in public transport use is statistically significant. These findings and insights guide policymakers and transport practitioners in appraising the effectiveness of new MaaS systems, especially in car-dependent regions in the world.