An apparatus for the automatic release of passenger protection devices in motor vehicles in the event of an accident has a sensor (35) having a mass (10) secured outside the center of mass (11). This mass (10) generates a comparably high torque in the suspension in the event of both positional change and rotational acceleration. These torques are detected with known measuring methods and split, with the aid of a high-pass filter (36) and a low-pass filter (40), into a high-frequency and a low-frequency portion. The high frequency portion corresponds to the rotational acceleration, from which the rotational velocity is obtained by means of an integrator (38). The low-frequency portion corresponds to the position of the motor vehicle. Thus both measurement variables that must be detected for releasing a roll bar are obtained with a single sensor (35).