A method of determining a yaw acceleration

A method of determining the yaw acceleration of a vehicle body 10 is disclosed, the method including the steps of: measuring the transverse acceleration agv, agh of the body 10 at at least two positions, using transverse acceleration transducers 16, 18 spaced apart along a longitudinal axis C/L through the body 10; determining the difference (agh - agv) in transverse acceleration between the two positions 18, 16; and dividing said difference by the distance d between said positions.