Local Traffic Control Measures

Targeted traffic control – ad hoc as well as strategic
avoiding congestion
avoiding accidents


Traffic Control

In order to locally improve traffic flow our systems use various methods to analyse sensor data for traffic and environment and determine control measures that can be triggered automatically. Traffic control is either implemented directly by indication of mandatory regulations or indirectly using warnings or traffic information.
The systems can also be operated semi-automatically, i.e. the operator will be asked and will then take the final decision before activation of a control measure.

The following mechanisms are, besides others, used to perform section control:

  • Speed harmonisation based on traffic volume
  • Lorry passing ban, in combination with speed reduction where required, based on HGV ration and traffic volume, and in case of heavy speed differences on different lanes
  • Warning of skid hazards with mandatory speed reduction
  • Congestion warning with step by step speed reduction

Ramp metering may be used on heavily loaded highways. It reduces negative impact on the highway by regulation of the entering traffic at slip roads. Using traffic signals vehicles are restricted to enter only individually or in small numbers, which prevents bulks of vehicles from entering the highway at once.

On road sections with temporary, very high traffic volume the above mentioned methods may not be sufficient to avoid traffic disturbances during peak hours. Here the temporary use of the hard shoulder offers a solution to cope with the temporary traffic demand and avoid expensive road extensions. Depending on the traffic volume the hard shoulder is opened or closed for traffic using variable message and traffic signs. CCTV surveillance assures that the hard shoulder is free from obstacles, e.g. broken down vehicles.

Traffic problems are very often caused by insufficient capacities in intersections and are strongly depending on the current situation. Dynamic lane assignment allows to react on the traffic flow in the intersection and to assign lanes to those flows with high traffic volume. Another method is the so called tempo split, which uses lane specific speed limits to harmonise traffic merging flows.

All traffic control measures can be also activated via a comfortable, graphical user interface. Measures (e.g for roadwork, accident) may be freely predefined, stored and recalled later for activation.