Improving Traffic Flow with C-ITS in PTV Vissim and LISA Lights

In an era where smart mobility is transforming urban transportation, Cooperative Intelligent Transport Systems (C-ITS) have emerged as a groundbreaking technology. C-ITS fosters real-time communication between vehicles (V2V), infrastructure (V2I), and other road users, such as cyclists and pedestrians. This technology significantly improves traffic efficiency, safety, and environmental sustainability. The potential of V2I communication, e.g. for smart signalization strategies, can be analyzed in PTV Vissim, a leading multimodal traffic simulation tool, in conjunction with LISA-controlled traffic lights.

The Challenge of Traffic Control

Managing urban traffic efficiently is a complex task. Road space is limited, and conflicting vehicle movements often create congestion and inefficiencies at intersections. Traditionally, traffic control systems relied on fixed-time signals or detection-based adaptive systems. While detection already allows for a reaction to the current traffic situation, it relies on external observation of traffic participants and does not know e.g. about the purpose of a vehicle movement like a first responder vehicle or other factors influencing priority.

PTV Vissim: A Powerful Traffic Simulation Tool

PTV Vissim is a multimodal microscopic traffic simulation software that models individual vehicle interactions with infrastructure, including signal-controlled intersections. The software allows planners to analyze and optimize traffic infrastructure in a controlled, simulated environment before implementing changes in the real world. This capability makes it an ideal testing ground for intelligent signal control strategies, including C-ITS-based solutions.

How C-ITS Enhances Signal Control

C-ITS enables bidirectional communication between vehicles and traffic signals, providing real-time information that improves traffic management. Traditional detection systems, such as inductive loops or video cameras, offer limited information (i.e., vehicle presence). In contrast, C-ITS-equipped vehicles can transmit data about their type, speed, position, and intent, allowing traffic signals to optimize green time dynamically.

With LISA-controlled traffic lights, the communication process becomes even more refined. LISA is a widely used tool for designing and implementing traffic signal control logic. When integrated with C-ITS, LISA receives real-time vehicle data and adjusts traffic signals accordingly, providing benefits such as:

Prioritizing Emergency Vehicles:
Emergency responders can send priority requests to traffic signals, ensuring a green light upon arrival.

Optimizing Public Transport Flow:
Buses and trams equipped with C-ITS technology can request priority passage, reducing delays and improving schedule adherence. Unlike traditional point-based prioritization systems, which rely on predefined communication points, continuous C-ITS communication allows real-time updates to signal controllers.

Implementing C-ITS in PTV Vissim

Activating C-ITS in PTV Vissim simulations involves enabling vehicle-to-infrastructure (V2I) communication attributes within the simulation environment. Steps include:

1. Configuring the Signal Controller: Selecting a V2I-prepared signal controller like LISA with capabilities to receive and process real-time vehicle data.
2. Assigning MapLane Numbers: Each lane in the simulation is given a unique ID, allowing the signal controller to track approaching vehicles.
3. Activating Vehicle Communication: Vehicles in the simulation are assigned attributes that enable them to send data to the signal controller.
4. Running the Simulation: Vissim processes the real-time communication data, and LISA adjusts traffic signals based on predefined logic.

In the simulation environment, planners can observe how different vehicle types (e.g., emergency vehicles, buses, private cars) interact with traffic signals under C-ITS conditions. Metrics such as average wait time, queue lenghts, and intersection throughput can be analyzed to assess the impact of intelligent traffic control.

Future Implications of C-ITS

As more vehicles become equipped with C-ITS capabilities, the potential for optimized traffic control grows. While today’s applications focus primarily on public transport and emergency vehicle prioritization, future use cases may include:

• Dynamic lane management: Adjusting lane assignments based on real-time traffic conditions.
• Cooperative maneuvers: Automated vehicle coordination to navigate obstacles safely.
• Pedestrian and cyclist integration: Providing crossing alerts and prioritization for vulnerable road users.

Conclusion

C-ITS is revolutionizing vehicle-to-infrastructure communication, and its integration with PTV Vissim and LISA-controlled traffic lights makes its transformative potential measurable. By leveraging real-time data exchange, cities can create smarter, safer, and more efficient traffic systems. As adoption increases, these advancements will pave the way for a future of connected and cooperative urban mobility.