Building a Motorway Digital Twin in SUMO: Real-Time Simulation of Continuous Data Stream from Traffic Counters

In contrast to prevailing studies, in this paper, we focus on the application of microscopic simulation during system run-time by using fine-grained actual traffic data streams from motorway traffic counters as input to on-the-fly synchronized Digital Twin of the Geneva motorway (DT-GM). Particularly, motivated by the lack of detailed steps on how to systematically use third-party controllers to dynamically generate and calibrate traffic flow in running simulation scenarios in the microscopic traffic simulator SUMO, we present technical details of methodological approaches used to build DT-GM in SUMO. In this context, we highlight the dynamic flow calibration (DFC) mechanism based on the calibrator objects embedded in SUMO, as well as the dynamic rerouting. Both of which can be controlled (adjusted) during the simulation run-time by interacting with a third-party controller through the SUMO TraCI interface. These are essential building blocks of DT-GM, which are used to dynamically generate the desired traffic volumes and continuously calibrate the simulated traffic scenario as the corresponding physical traffic dynamics change. Thus, the actual speeds and number of vehicles with the vehicle class recorded by the traffic counters in minute resolution are directly fed into the running DT-GM. Accordingly, DT-GM continuously adjusts to its physical correspondence in real-time, ensuring calibration on-the-fly as opposite to traditional offline calibration.