An arrangement for triggering a motor vehicle safety device. The arrangement incorporates a proximity sensor (1) which is configured to provide a proximity signal related to the distance to an object and/or the relative speed between the object and the sensor (1). The arrangement also includes an accelerometer (2) and a first processing unit (3) which is configured to perform an arming algorithm on signals received from the proximity sensor (1) and the accelerometer (2). A second processing unit (6) is provided to perform a crash algorithm on signals received from the proximity sensor (1) and the accelerometer (2). The arrangement incorporates a logic gate (4) to generate a triggering signal (5) in response to simultaneous output of signals from the first processing unit (3) and the second processing unit (6).