Reversible adaptive safety systems will become much more important with the implementation of an extensive pre crash sensing. With early detection of critical driving situations it will be possible to reduce, for instance, belt slack with the belt pretensioner. Furthermore, the prevention of Out Of Position (OOP) situations will be possible by 'pulling' the passengers out of the danger zones of the airbags with an active belt system. The usual belt force limitation used up until now can be extended in the direction of a passenger specific belt force control. This means pretensioning and limiting the belt force depending on specific passenger data, such as weight. In this paper a MADYMO vehicle model with an occupant and a finite element modelled belt system will be presented. The mechatronic belt system is equipped with an actuator and Sensors measuring the current belt force. Using the measured belt force an adaptive command variable can be calculated. The actuator applies the force to the belt system. The simulation results show the reduction in occupant injuries. Furthermore modelling extensions and possible fields of application are shown in this paper.