Device for triggering a vehicle safety device

An arrangement for triggering a vehicle safety device such as an airbag or seat belt tensioner that avoids inadvertent triggering of the device, The arrangement incorporates a proximity sensor 1 (e.g. radar) measuring the distance to an obstacle and/or the relative speed of the obstacle with respect to the vehicle, and an accelerometer 2. Both sensors are connected to two sensor signal processing units 3, 6. One of the processing units 6 performs an arming algorithm on signals it receives from both the acceleration sensor 2 and the proximity sensor 1, whilst the other processing unit 3 performs a crash algorithm on the signals it receives from both the accelerometer 2 and the proximity sensor 1. A safety device trigger signal 5 is generated only when both processing units simultaneously produce an alarm signal.