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Overview of the signaling of four cantons

A unified operation for all traffic control systems of the Zentras territorial unit.

Multi-part blog series on more road safety and traffic quality (part 3/7)

An accident in the Lucerne city tunnel, in the middle of the evening rush hour. A traffic jam forms immediately and grows rapidly. The staff at the traffic management center in Emmenbrücke and the Lucerne police are now called upon to minimize the impact of the accident on traffic. There is a clear division of tasks: the police lead the operation on site and, depending on the situation, also provide rescue vehicles from the ambulance service or even the fire department.

The traffic management center, meanwhile, is concerned with limiting the consequences of the incident for the wide-ranging traffic flow as far as possible, i.e. informing road users and rerouting them if necessary. For these tasks, traffic control systems are available to the personnel, with which a wide variety of traffic signals can be quickly controlled from the control centers. It is important for the operators to have a complete overview of all systems and, if necessary, to be able to efficiently control neighboring sections on the downstream road network (secondary nodes).

Traffic Management Center
Traffic Management Center
Traffic signals that can adapt to the current situation

On Switzerland's national road network, road users encounter a wide variety of traffic signals. First of all, a distinction must be made between static and dynamic signals. The static signals always show the same image; in simple terms, they are printed metal panels. The dynamic signals, on the other hand, can be controlled from the control centers - the image displayed can therefore be adapted to the situation at hand. These signals allow police and traffic management personnel to react to events. A distinction is made between different types of dynamic signals. The tunnels at the portals, for example, are equipped with traffic lights.

Portal traffic lights
Portal traffic lights

These are normally always switched off, but can be switched to red if the tunnel is to be closed. Then there are flashing signals that are switched on to warn of an unusual situation. Another important tool are the lane light signals (FLS), which can represent a green arrow, a red cross or a yellow arrow and are used to temporarily close individual lanes.

Lane light signals
Lane light signals

For wide-area traffic guidance, traffic management has at its disposal, for example, the alternating text displays, which can display three lines of text and a signal.

In addition, there are also special versions of the green directional signals, which can display special images for signaling detours in addition to the normal image. Last but not least are the speed and danger signals, of which there are also versions that can show different views as required.

Prism change signals
Prism change signals

These dynamic signals must output timely, correct and, above all, consistent information and instructions. This task is performed by digital traffic control systems. These cover the road network section by section and provide operators with a convenient user interface for switching all signals. For the police, whose task is the local management of incidents, these traffic control systems are the ideal tool. In contrast to the police, traffic management is responsible for wide-area information and for traffic detour. Because traffic control systems typically have rather limited geographic coverage, an event with wide-area impacts may require traffic management personnel to operate a large number of traffic control systems more or less simultaneously. As a result, response time can suffer - road users may not be informed or rerouted in time.

This can be remedied by regional traffic control systems that orchestrate a large number of local traffic control systems like a conductor, and ensure

signals in a large region can be switched simultaneously and in coordination with each other.

The region of the Zentras territorial unit
The Swiss national road network is operated by eleven territorial units. Area unit 10, also known as GE X or GE Zentras, covers the area of the four cantons of Lucerne, Zug, Nidwalden and Obwalden. This central part of the freeway network includes the traffic hub of Lucerne, is close to important traffic locations such as the city of Zurich or the Gotthard, and represents an important part of the north-south axis through Switzerland. The benefits of a regional traffic control system were obvious in this region. The project for the realization of the regional traffic guidance system "VM Zentras" was started in 2011, and Eraneos was allowed to supervise the project as project author from planning to procurement to realization.
Challenges in the project
In order for the regional traffic control system to fulfill its role, it needs a communication channel to each local traffic control system. When the traffic control systems, some of which were already older, were built, regional interconnection was not yet an issue, which is why the local systems did not have any corresponding interfaces. In the project, therefore, not only the new regional traffic control system had to be planned and implemented, but also all local traffic control systems had to be retrofitted with a corresponding interface. For this purpose, Eraneos commissioned and coordinated numerous specialized companies. After the implementation and acceptance of the individual systems, the interaction of the overall system had to be tested. More delicate operations, such as large-scale detour, could not be tested during the day when traffic was heavy, but only at night. This was done in cooperation with the police, who were on site at important points with patrol vehicles.


Who likes to get stuck in a traffic jam for hours because information about an accident ahead was not received in time? With the "VM Zentras", the traffic management center in Emmenbrücke has a tool with which the staff can quickly inform about traffic problems and, if necessary, initiate detour via the traffic control systems.

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