A method of operating a hydraulic safety system 38 includes determining a relative roll angle, determining a relative a slip angle, determining a yaw rate and determining a pressure build rate for the hydraulic safety system 38 in response to a relative roll angle, the yaw rate, slip angle, and yaw rate. The method further includes determining a precharge pressure level in response to the relative roll rate, the slip angle and the yaw rate and controlling the safety system 38 in response to the precharge pressure level.