Most car suspension are compared of passive spring and damper devices. It is possible to improve the suspension performance by using intelligent suspension systems. In this paper, the four degrees of freedom models of car suspension system are analysed to provide insight into the active suspensions compared with both the twin accumulator and conventional passive suspensions. Passenger discomfort, suspension working space and dynamic tyre loading parameters are calculated for these suspension systems. The vehicle itself is treated as a rigid body. The effect of using twin accumulator and active suspensions to obtain improved ride is discussed. The results obtained indicate that the active suspension system is superior to both the twin accumulator and passive suspensions in terms of ride performance.