Traffic control system

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VBA on the A4 near Cologne in Germany

The term traffic control system ( VBA for short ) is usually used for technical facilities on motorways and expressways that were set up by the operator of the road (road maintenance company) in order to control the flow of traffic on one or more sections, at junctions or in the entire network through collective influencing improve. Traffic control systems are traffic engineering systems for traffic management purposes .


In addition to improving traffic quality ( level of service ) and preventing unstable traffic conditions (shock waves and traffic jams), the task of the traffic control system is to increase traffic safety by reducing the speed variance in the vehicle group and optimally distributing trips to the available infrastructure. Furthermore, traffic control systems are operated to secure dangerous routes (long tunnels, mountain routes) and obstructions (construction sites, accidents, tunnel closures, traffic jams, fog).


Distraction from the congested A 5 due to the construction site onto a district road

The following types of traffic management systems are used:

  • Node control systems serve to separate competing traffic flows at points of conflict in traffic. This includes traffic light signaling systems (VLSA) at level junctions and ramp controls at motorway entrances.
  • Network control systems ( NBA for short ), also known as network control systems, use variable signposting systems to direct traffic from overloaded or heavily loaded routes to those network parts that still have reserves. A diversion of the motorway traffic into the secondary network is generally not desired and is usually only allowed if the high-level road is completely closed.
  • Route control systems ( SBA for short ) serve to stabilize the flow of traffic on a node-free route and include systems for speed homogenization (variable message signs ) and lane signaling (blocking of lanes), as well as systems for giving priority to journeys on specially dedicated lanes ( bus lanes , HOV lanes ).
  • Temporary hard shoulder clearance ( TSF ) enables the hard shoulder to be opened to flowing traffic on heavily used expressways. The capacity of the section will also be increased.
  • Flow control systems are used to meter the flow on expressways in a targeted manner when traffic is high. This prevents vehicles from constantly driving onto the expressway and thus disrupting or slowing down the flowing traffic.


Prism signposts and a light panel with an accident notice

Traffic management systems are made up of the following subsystems:

  1. Sensor systems (induction loops, infrared sensors, video) for recording traffic parameters (traffic volume, traffic density, local speed).
  2. Computer centers and sub-centers for evaluating the data streams and for activating the coordinated strategies.
  3. Transmission devices for communication between the field devices and the control centers.
  4. Collective actuators (signals, traffic signs) to convert the switched strategy into visual symbols for the drivers.
  5. Traffic monitoring devices to ensure compliance with the activated strategies by road users.


The effectiveness of traffic control systems has been tested and confirmed in the course of many investigations and studies. It was found that the number of accidents on accident-prone routes could be reduced by 20 to 30% with the help of route control systems, depending on local conditions. Furthermore, route control systems lead to a stabilization of the flow of traffic (reduction or even prevention of congestion), especially when there is a high volume of traffic. The capacity increase achieved in the section is around 5 to 10% (compared to similar sections without VBA).

Network control systems show a similarly positive balance. With their help, it is possible, depending on the road network, to divert up to 15% of the total traffic to alternative routes. In this way, the traffic load on the original route can be reduced and the traffic quality can be improved.

Traffic management systems in Europe


The further development of systems for influencing and controlling traffic is a priority of the German government in terms of transport policy. An overview and a list of existing and planned traffic control systems can be found in the “Road Traffic Telematics Project Plan 2015” at the Federal Highway Research Institute .


Traffic control system on the Inntal Autobahn (A 12) near Radfeld in Tyrol

In Austria, around 800 kilometers of driving direction - 19 percent of the entire network - can be controlled using VBA. For example, the most important transit routes are equipped with traffic control systems. These include the West Autobahn A 1 (VBA Umwelt), the Tauern Autobahn A 10 (VBA Umwelt), the Inntal Autobahn A 12 and the Brenner Autobahn A 13. Further VBAs are installed on the following motorways and expressways:

In addition to the VBA that is already in operation, further systems are planned or under construction in Austria. Rough plans already exist for the cities of Graz , Salzburg and Linz .


In Poland , the construction of systems for traffic management and traffic control is increasing continuously. The first systems were installed as part of the toll preparation on the sections of the A4 motorway from Wroclaw to Gliwice (160 km) and the A2 motorway from Konin to Łódź (103 km) in 2010. Furthermore, the entire stretch of the A8 motorway and the S69 expressway were equipped with modern traffic control systems.

The "National System of Traffic Control " ( Krajowy System Zarządzania Ruchem , KSZR) for motorways, expressways and national roads is to be created by 2014. The tasks of this system will be to monitor traffic flow, weather conditions, the state of maintenance of roads and accidents, and consequently manage the situation on the roads, provide information about traffic conditions and direct traffic to detours. Based on measurements from weather stations, the system will display warnings for drivers on the systems. There will be reports of a slippery surface, cross wind, fog or accident. In addition, the speed limit is displayed on the systems, which will vary depending on the driving conditions. This system should cost a total of 500 million zlotys . The most important roads in the country are to be equipped with traffic management systems by 2016.

See also

Web links

Commons : Traffic management systems  - collection of images, videos and audio files

Individual evidence

  1. a b c Collective traffic control systems on federal highways  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF file, 542 KB)@1@ 2Template: Toter Link /  
  2. Accompanying research and supplement to the leaflet 'Determining the effectiveness of traffic control systems ( Memento of the original from May 12, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF file; 1.65 MB) @1@ 2Template: Webachiv / IABot /
  3. Federal Highway Research Institute: Road Traffic Telematics Project Plan 2015
  4. ASFINAG: Telematics on the street ( Memento of the original from May 12, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  5. Autostrada będzie inteligentna (Polish)
  6. System zarządzania ruchem na A4 (Polish)
  7. AOW. Piękna droga, ale dokąd prowadzi kierowców? (Polish)
  8. Na potęgę okradają AOW, więc może być niebezpiecznie (Polish)
  9. Centrum zarządzania autostradami w Milówce ma powstać w 2014 roku (Polish)
  10. Zamiast dróg będzie system zarządzania ruchem (Polish)
  11. Z Zabrza płynąć będą ostrzeżenia dla kierowców na trasie A4 i A1 (Polish)