An improved method and associated system for controlling the brake system of a vehicle train including a tractor vehicle and a trailer vehicle, wherein a control device disposed in the tractor vehicle is adapted to initiate automatic braking of the trailer vehicle, and wherein the conditions of the driving roadway, especially the coefficient of friction, are taken into account in braking of the trailer vehicle. The intensity of braking of the trailer vehicle is reduced by the control device when a coefficient of friction smaller than a predetermined minimum value is detected between the vehicle train or parts thereof and the driving roadway. One application of the invention is in load trains equipped with means for preventing rollover or overturning.