On the basis of control loop components, it is explained which occurrences of accident-relevant driving manoeuvres can lead to road accidents. These manoeuvres are simulated with the aid of the driving dynamics simulation model MEDYNA. In extreme situations, the variations in the vehicle parameters lead to an unstable behaviour, which as a rule precedes an accident, meaning that limit values and/or areas representing the criterion for study of an accident, or rather, of its avoidance, can be established. The accident-relevant driving manoeuvres, the described quantities of the actions introduced by the driver, such as braking, accelerating and steering, as well as the spectrum of vehicle-specific parameters are deduced from the analysis of the material provided by the accident research group of Medizitrische Hochschule Hannover and Technische Universität Berlin (MHH/TUB). The initial results on the avoidability study, which were achieved in a research work sponsored by the Bundesanstalt für Straßenwesen, are presented.