A brake control system has an electronic control unit such that, when the motor vehicle is at a standstill, an automatic parking brake function can be activated by the control unit. In the presence of an activation condition for the parking brake function, the brake pressure required for this purpose can be determined at least in a manner dependent on the longitudinal inclination and in a manner dependent on an estimated normal force distribution of all of the wheels and/or an estimated capability of all of the wheels to transmit braking and/or drive torque to the underlying surface. Here, the brake pressure can be predefined to be higher the more wheels have a reduced normal force.