The challenge: Coordination and synchronization of multiple traffic lights
For traffic light systems, high availability and high throughput are essential: Installations must run without interruption and traffic should also flow as optimally as possible. Red or green phases should not be too short, nor too long for best traffic flow. The installation must additionally handle many variables: maneuvering construction machines, slow vehicles such as buses and delivery traffic, but also the change in behavior of road users in response to the construction site situation. In addition, when a traffic jam begins, information about the traffic situation should be provided from the access roads so that, if necessary, a further influx of traffic can be contained.
The solution: Visualization, remote diagnostics and remote control
The solution is a communication concept for the tunnel alarm and for the traffic jam detection. Imo TRAFFIC uses gateways from INSYS icom for this purpose in order to parameterize the traffic light network remotely and intelligently and demand-driven with the help of relevant data. A remotely accessible dashboard on the gateways visualizes all relevant status values, enabling efficient remote diagnostics and monitoring.
Since there is always a very high volume of traffic, especially on nice days, and the associated tailbacks, additional traffic jam sensors were installed at two locations. An evaluation unit and an ECR router from INSYS icom are located at both traffic jam sensors. These traffic jam sensors report the traffic condition to the Traffic Broker placed in the router of the 1st traffic light. Depending on the states, it is defined which pre-programmed traffic jam image represents the current event. This information is then sent via an MQTT protocol to two other routers located along the incoming A6 and A8 highways. There is one LED wall each next to an INSYS IO unit with an ECR router. This IO unit “feeds” the LED screens with the respective pre-programmed traffic jam image, which is then displayed. In this way, road users are kept up to date on the current traffic situation.
Source: INSYS icom
A tailback into the tunnel is to be avoided for safety reasons. To ensure this, there is again an IO unit from INSYS icom with the ECR router at the tunnel control center, the Werkhof in Interlaken. This sends its status information to a safety broker integrated in this unit. The safety broker sends this information on to the 3 traffic lights. As soon as such a tunnel alarm arrives there, all traffic lights switch to permanent red. At the same time, the personnel from the construction site security service and the traffic service are informed via SMS. It takes the incident services about 10 minutes to get to one of the tunnels. Until then, traffic services are tasked with turning traffic around and allowing it to move away from the closed section if possible. The traffic lights leading away from the roadway will also remain red to allow incident services to overtake the traffic jam from either end of the jam via the opposite lane to get to the incident scene as quickly as possible. The security service can then, at a later point in time, in consultation with the event services, remove the block at the traffic lights via SMS. After that, the traffic lights switch back to normal.