Abstract: The present invention provides, with reference to the figure, a vehicle suspension system comprising an actuator (10) connected between the body (17) of a vehicle and a wheel and hub assembly (18) of the vehicle. A source of pressurized fluid (20) and an exhaust for fluid (24) are provided along with a valve (22) for controlling flow of fluid to the actuator (10) from the source of pressurized fluid (20) and/or from the actuator (10) to the exhaust for fluid (24). A sensor (27, 28, 30, 31, 32, 33, 34, 35, 41) is used to generate signals of sensed variable vehicle parameters. A control system for the vehicle suspension system is used which has a processor (25, 20) which processes the signals generated by the sensor (27, 28, 30, 31, 32, 33, 34, 35, 41). The processor (25, 26) outputs a control signal to the valve (22) and thereby controls the actuator (10). The processor in normal operating conditions uses a first set of preprogrammed constants (e.g.