A method is disclosed for obtaining a signal representing motor vehicle acceleration. The method involves obtaining a high pass filtered vehicle acceleration signal and a low pass filtered vehicle acceleration signal. One of these signals (preferably the high pass filtered signal) is obtained based upon the net driving force applied to the vehicle, which can be used to obtain an estimate of acceleration by means of an adoptive vehicle model (28). The other signal is obtained by measurement, for example by differentiating a measured vehicle speed signal with respect to time. Adding the two filtered signals together gives a vehicle acceleration signal of potentially good quality.