Integrating Connected and Automated Shuttles With Other Mobility Systems: Challenges and Future Directions

Connected and Automated Shuttles (CAS) are emerging technologies recently introduced into urban intelligent transport systems to enhance their efficiency. However, the majority of existing studies primarily concentrate on their design and public acceptance, while their integration to complement more conventional mobility systems is largely ignored. Indeed, the integration of CAS with existing transport systems represents a promising opportunity to improve the overall efficiency and safety of existing mobility services, be it offered to citizens or companies. However, this integration presents significant challenges for mobility service operators, who must consider the potential impact of these new technologies on traffic patterns, infrastructure investments, and travel behavior. This paper reviews the current state of connected and automated shuttle's technologies, including the different experiments and pilot projects in Europe for the transport of people, goods or both, in addition to the scientific efforts to build new services (e.g., optimisation and AI-based models). We discuss the challenges that mobility service providers face when planning for the long-term integration of CAS, and propose a digital twin approach to help overcome these challenges. The proposed approach is based on advanced simulation and modeling software that can create realistic 3D representations of transport systems and has the potential to simulate the impact of CAS on traffic patterns and infrastructure investments. This paper serves as a starting point for future investigations on the integration of CAS with the existing mobility systems by identifying research gaps, limitations and challenges, and potential areas of research to overcome these challenges and improve the effectiveness of future mobility services.