Tunnel

Signaling systems

The signaling systems dynamically indicate the applicable speed limit according to the volume of traffic. In addition, they are also used for dynamic traffic control and display in the event of a traffic jam, accident or other impairment of one or more lanes.

Video surveillance systems

Video surveillance in motorway tunnels is also becoming increasingly important. In the past, this was simply used for visual monitoring of the traffic inside the tubes. Thanks to increasing digitization, there are many more possibilities today. Above all the so-called automatic event detection. Based on the video images from the cameras, this recognizes whether there is any danger inside or outside the tunnel. The event detection detects whether a traffic jam is or will arise, whether an accident has occurred or whether a fire has broken out. Objects on the road are also detected so that road users can be warned at an early stage. As a result, video surveillance is also used more and more frequently for fire detection.

Lightning systems

The lighting systems ensure that lighting is as balanced as possible in normal operation and should be similar to the outside brightness. That is why the lighting is also subdivided. On the one hand in entrance lighting and on the other hand in drive-through lighting. The entrance lighting helps the eyes to get used to the darker surroundings when entering the tunnel. This lighting is therefore regulated based on the currently prevailing brightness at the tunnel entrance and continuously decreases in the tunnel. At night it switches off completely.
The drive-through lighting, on the other hand, tends to be geared towards the volume of traffic rather than the external brightness. Because in the tunnel itself, you can’t see the outside world. But you can see – or rather – you have to see how many vehicles are in front of and next to you.
Like all other systems, the lighting must also react to special situations such as fire and accidents and ensure sufficient brightness at the scene of the accident
Furthermore, the optical guidance devices on the tunnel floor are used more and more. The function of this type of lighting is to help the fleeing person to find the correct escape direction in the event of a fire, if there is heavy smoke in the tunnel.

Tunnel ventilation systems

Tunnel ventilation systems are among the most important systems in a tunnel. On the one hand, it ensures fresh air in the tunnel and, in the event of a fire, is also the system that can save human lives. In the first case, it checks and regulates the air in such a way that exhaust gas values in the tunnel tube remain at a level that is harmless to humans. It is not only the classic toxins such as CO2 or NOX values that count, but also the clouding of vision (which is caused by rain, for example), which are decisive for a safe journey.
In the event of a fire, seconds make the difference between life and death. If a vehicle should catch fire inside the tunnel, the tunnel ventilation system ensures that, on the one hand, the toxic smoke is extracted on the spot, and on the other hand, enough oxygen can reach the people through the controllable air flow. This enables those who have been involved in an accident to escape with as few obstacles as possible.