## 8 Discussion
### Opportunities and Challenges
In [101], a multi-level decision framework was proposed for the design of urban mobility policies based on multi-criteria resource allocation decisions at different levels. Additionally, an interactive scenario-simulation tool was developed in [101] to support decision makers. In summary, governance stakeholders play a pivotal role in taking action toward sustainable development by promoting enterprise and industrial transformation. However, existing studies on the role of governance stakeholders in shaping MaaS uptake are limited. Understanding how governance stakeholders might shape sustainability transitions and technology uptake is an important issue. The rapidly expanding research issues related to sustainable multi-modal MaaS are both multidisciplinary and interdisciplinary in nature, and they have significant impacts on stakeholders. Achieving the vision of sustainable multi-modal MaaS requires practitioners, experts and stakeholders from different disciplines to draw on their disciplinary knowledge, work collaboratively, and integrate knowledge and methods using a true synthesis of approaches. The collaborative actions of a wide range of stakeholders and practitioners can lead to a better understanding of the concept of MaaS and generate the depth of knowledge [153] needed for its inception, planning, and implementation, based on previous MaaS pilot experiences. For example, several previous MaaS pilots have shown that public-private collaboration or partnership is a crucial element in the realization of MaaS, though it introduces new issues for transport governance [154, 155]. Balancing the control of public transport service providers with the interests of private sector mobility service providers poses significant challenges in the development of both urban and rural MaaS. Previous experiences from MaaS initiatives in cities around the world provide valuable references for the development and implementation of sustainable MaaS. In what follows, we briefly review the MaaS experiences from Helsinki, Singapore, and Shanghai. Helsinki is a pioneering city in the successful implementation of a MaaS solution [156]. In 2017, the Whim app was launched by MaaS Global. The city's approach has been studied extensively, offering insights into the factors contributing to its success. Key factors in Helsinki's MaaS success include: (1) a user-centered app to integrate various transportation modes--public transit, bike sharing, e-scooters, taxis, and car rentals; (2) legislative support requiring transportation carriers to release travel data for planning purposes as well as make ticketing available to third-parties for application development; (3) reliable public transport infrastructure; and (4) significant reductions in environmental impact by shifting users from private cars to public transport and shared services. The early success of the Whim app led to its operation in several countries, including Finland (Helsinki and Turku), Austria (Vienna), Belgium (Antwerp), the United Kingdom (Birmingham), Japan (Tokyo), and Switzerland (various cities nationwide). However, MaaS Global, the Finnish company behind Whim, filed for bankruptcy in March 2024. In April 2024, Dutch mobility platform umob acquired MaaS Global. There are many studies related to the development of MaaS in Singapore [157, 158, 159]. The Zipster app, launched in 2019, was the first all-in-one transport app in Asia to integrate various mobility services, including public transit, ride-hailing, bike-sharing, and carsharing [160]. However, it was discontinued after two years due to limited user adoption and profitability concerns. Experts suggest that Singapore's already efficient and affordable public transport system may have reduced the perceived need for such an integrated platform. Despite the setbacks of the Zipster app, a survey in 2024 indicated that 56% of Singapore's utilized shared mobility services--such as ride-hailing, carpooling, and bike-sharing--typically two to five times per week.