A trailer device for driving stabilization of vehicle combinations is provided. In order to design a device for driving stabilization of passenger vehicle trailers in a cost-effective and simple manner, a brake system for braking the trailer by an overrun brake and for stability regulation is designed so as to have separating valves, switching valves, inlet and outlet valves and a pressure build-up pump. A stabilizing coupling is also connected by means of a second pressure medium pump to actuators which can vary the clamping force of the stabilizing coupling between the trailer and tractor vehicle if the second pressure medium pump conveys pressure medium from the storage tank into or out of the actuators.