As C-ITS adoption accelerates, simulation tools are helping cities test and refine connected signal strategies without disrupting live traffic
PTV Group (part of Umovity) – ITS European Congress Istanbul – Booth C4
Urban intersections remain one of the most critical bottlenecks in transport networks. As traffic volumes grow and mobility patterns become more complex, Cooperative Intelligent Transport Systems (C-ITS) have emerged as a promising technology with significant potential to improve traffic flow, safety and operational efficiency. An important tool for evaluating such connected strategies is microscopic traffic simulation.
“Road space is limited, so it is all about using existing infrastructure in the most efficient way. C-ITS is becoming increasingly important for cities worldwide,” says Matthias Pfriem, senior product manager for PTV Vissim. “Simulation helps traffic planners and engineers create a realistic testing ground for intelligent signal control, allowing them to plan, test and optimise strategies before implementation.”
Connected by design
C-ITS enables real-time bidirectional communication between vehicles (V2V), infrastructure (V2I) and other road users. Connected vehicles transmit continuous data including position, speed, vehicle type and trajectory. For traffic control systems, this greatly expands the available information base and enables more adaptive and predictive signal control strategies.
“Activating C-ITS in PTV Vissim simulations involves enabling V2I communication attributes within the simulation environment,” says Pfriem. “When those connected vehicle attributes are provided to a V2I-ready signal controller, that real-time information can be used directly in the signal control strategy for prioritisation of selected vehicles or for general optimisation of intersection performance. The simulation serves as a test-bed for exploring different control strategies in different traffic conditions and connectivity scenarios.”
From data to dynamic control
Within the simulation, vehicle data is transmitted to signal control logic, which dynamically adjusts signal phases. Planners can analyse how different penetration rates and demand conditions affect intersection performance or how signal strategies respond to real-time vehicle data under varying conditions. Key indicators such as delay, queue length and intersection throughput can then be measured and compared across scenarios.
One key application is signal priority for specific vehicles. Emergency vehicles can send priority requests, allowing the signal controller to provide a green phase on arrival, reducing response times and improving safety.
Public transport benefits similarly. “Buses or trams communicating directly with the signal controller can request priority far more flexibly and precisely than traditional systems,” says Pfriem. Continuous communication enables signals to respond dynamically to approaching vehicles, improving schedule adherence while minimising impacts on general traffic.
Network-wide gains
Beyond priority applications, connected traffic control also supports more advanced traffic management strategies. Continuous vehicle data helps reduce stops, shorten queues and increase capacity without infrastructure changes.
Modelling the road ahead
Simulation enables these strategies to be tested safely and systematically. Planners can evaluate configurations, identify challenges and quantify benefits before field implementation, reducing risks and supporting data-driven decision-making.
“As more vehicles become equipped with C-ITS capabilities, the potential for optimised traffic control will continue to grow. Future use cases range from dynamic lane management to improved safety for vulnerable road users. Simulation helps make this potential measurable. And as we model V2I agnostic from the communication path, PTV Vissim can be used to test approaches with direct communication via ITS-G5, via 5G cellular communication or indirect communication via cloud-backbones,” concludes Pfriem.
