A Challenge-Led Digital Twin Federation Architecture For Urban Passenger Transport Decarbonisation

Urban transport is one of the largest contributors to global greenhouse gas emissions, and decarbonising transport systems is a key policy objective in many countries. Existing planning tools, when used in isolation, often failed to capture the interplay between dynamic demand and supply in transport systems. This highlights the need for a tool that enables learning-by-doing approaches for planning ambitious decarbonisation targets. Digital twin (DT) concepts have recently been proposed as adaptive decision-support systems that iteratively evaluate different engineering interventions as the physical system evolves. However, in the domain of passenger transportation, research is underrepresented, with limited insights into DTs’ definition and design. To address this gap, based on co-design with local stakeholders, this paper presents a conceptual architecture for a digital twin federation (FedDT) for the West Midlands region, UK. The proposed FedDT is designed to support both short-term operational and relatively long-term tactical, strategic mobility planning within a single framework. By integrating an ontology-based knowledge architecture, mobility-demand modelling, multi-level agent-based simulation, optimisation, stakeholder consultation, and modelling & reasoning frameworks, the FedDT enables iterative, bidirectional data exchange between the physical mobility system and its digital counterpart. In addition, the proposed FedDT follows a human-in-the-loop design, thereby ensuring the interests of relevant stakeholders are continuously integrated. The proposed architecture informs the development of key modules, including the Big British Bus Ontology, a multi-modal agent-based mobility simulation with railway integration, and optimisation models for transitioning to electric buses in the West Midlands. Overall, this paper applies and extends existing DT architectures for passenger mobility, provides an architectural foundation for ongoing FedDT module development in the West Midlands, and offers a transferable blueprint for regions seeking to leverage DT technologies to support transport decarbonisation.