Sprinx // Case Studies // RN88 – Tranchée Couverte de Firminy

RN88 – Tranchée Couverte de Firminy

The Challenge

The Firminy Tunnel, situated on the RN88 in the Loire department, is a critical urban bidirectional structure on the trans-European transport network (RTE-T) between Saint-Étienne and Le Puy-en-Velay. This vital connection experiences heavy traffic, necessitating stringent safety and monitoring measures.

The challenges faced in upgrading the Firminy Tunnel include:

  • High Traffic Volume: the tunnel is a key junction, leading to constant and heavy use, particularly by heavy vehicles.
  • Structural Constraints: the design of the tunnel limits the height at which cameras can be installed, complicating the prevention of obstructions.
  • Lighting Conditions: being a multi-lane, bidirectional tunnel with windowed sections, the mix of shadows and reflections poses significant challenges to the performance of traffic analysis systems.
Project details

End user: DIR Centre-Est (Direction Interdépartementale des Routes)

Partner: Bouygues Energie & Services

Loire department, France

2023

The Solution

Sprinx, in collaboration with Bouygues Energie & Services and supported by Egies Tunnels‘ project management, provided an AI-based AID system called traffix.ai, based on the Intel OpenVINO™ Toolkit. This system, integrated with the dragon management platform, interfaces with both the ITS and the video surveillance system of the DIR-CE central control room.

The deep learning module capabilities of the system, combined with the 3D object tracking technology, allowed for the accurate detection of incidents even in conditions with significant reflections and shadows caused by vehicle movements and filtered light from windowed sections. DIR-CE personnel, assisted by CETU experts (the French Centre for Tunnel Studies), conducted rigorous testing and validation to verify the system’s performance on a camera-by-camera basis. This process ensured the system met expected performance levels for detecting incidents such as stopped vehicles, pedestrians, wrong-way drivers, and smoke. Additionally, a period of regular traffic validation was implemented to monitor and fine-tune the system’s detection sensitivity for slowdowns and queues, ensuring its accurate performance in real-world conditions. The seamless integration of the AID system with the existing SPIE GTC system (ITS platform) facilitated unified management within the central ITS platform, further enhancing the operational efficiency and safety of the Firminy Tunnel.

The Result
  • Enhanced Detection Performance: Achieved high detection accuracy and reduced false alarms, enhancing the operational efficiency of the DIR-CE control room.
  • Unified System Management: Integration with the SPIE GTC system allowed for unified management of the Firminy AID system within the central ITS platform.
  • Improved Safety and Efficiency: Overall, the project ensured a safer and more efficient tunnel operation, aligning with both French regulatory requirements and the European directive for road tunnels over 500 meters on the trans-European network.
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