Scalable Framework for Behavior Execution of Mobility and Transport Digital Twins

The increasing complexity of smart city systems, particularly in mobility and transport domains, demands scalable and interoperable simulation frameworks for digital twins. To address these challenges, this paper introduces the Behavior Execution Framework for Digital Twins (BEFDIT), a modular, scalable solution designed to orchestrate heterogeneous behavioral simulations and predictions across different spatial and temporal scales. BEFDIT supports the co-simulation and co-execution of multiple simulation tools, both open-source and proprietary, through cloud/container-based infrastructures. BEFDIT facilitates real-time and offline management of simulations, dynamic resource allocation, and business model-driven service provisioning. It enables users to configure and manage Groups of Behavioral Executions, supporting independent, interoperable behavioral executors with persistent storage and web-based visualization. The framework's capabilities are demonstrated through the usage of SUMO simulator for urban mobility modeling, showcasing use cases in dynamic routing, congestion management, and real-time data generation for digital twins. Experimental results highlight BEFDIT's effectiveness in enhancing simulation scalability, interoperability, and decision support for smart city applications. The proposed solution can be adopted for what-if analysis frameworks, and for tactic/strategic planning, thus realizing an extremely valuable tool for smart city mobility. The solution has been implemented and is integrated into Snap4city Open-Source platform for Spoke 9 of the Italian National Center for Sustainable Mobility (CN MOST), and the CN MOST flagship OPTIFaaS and scalability SASUAM and adopted on CN HPC in Italy.