Traffic control systems improve safety
Improved traffic flow, more road safety, less congestion and a lower environmental impact - this is what we are aiming to achieve with traffic control systems (VBAs). The VBAs can promptly respond to sudden and unforeseeable incidents - in the event of an accident, for example, with recommendations for alternative routes.
How VBAs work
Sensors record traffic and environmental data along the motorways and expressways. The sensors detect traffic volume and speed as well as weather-related dangers such as wet conditions and reduced visibility.
Depending on these data, situation-appropriate speed limits or warnings are displayed automatically.
The operators perform many of the tasks. They work around the clock in our nine regional traffic management centres throughout Austria, and they oversee the entire network. When there has been an incident (such as accidents, breakdowns or lost parts on the road), they can use the VBAs to manually display speed limits, warnings or which lane to use.
"Why is speed limit 80 flashing up?"
There are several reasons why the speed limit within a VBA has to be reduced. In addition to the manual displays when there has been an accident or breakdown, the speed limit is also lowered (to a minimum of 60 km/h) if there is increased traffic volume, because of the resulting risk of congestion. The aim here is to balance out the traffic flow and thus to delay the congestion or ideally prevent it altogether. To avoid frequent switching, the VBA increases the speed limit again only once the traffic flow has normalised and the drivers are moving at an even speed again.
Types of traffic control systems
Route control systems
These balance speeds based on the prevailing conditions (accident, traffic volume, congestion, construction site, weather). They also display overtaking bans, lane changes and warnings.
Network control systems
These provide information about important incidents in the network (local, trans-regional and international) as well as diversions or blocked roads, and they suggest alternatives. They are usually located near motorway junctions.