Abstract
In this paper an overview is given of Automatic Incident Detection Systems and the demands that are made on those systems. The AID-system that is being developed by the Automatic Traffic Systems Laboratory is discussed. This system is based on a microscopic traffic model, describing the behaviour of individual motorists. Any deviation from the normal behaviour is scrutinized and if the deviations cause a dangerous situation other drivers will be warned. This method has become possible with the availability of payable computer power.