About a decade ago, it was difficult to compromise between the vehicle ride and handling requirements. Recently attempts have been made to satisfy the many conflicting requirements of vehicle suspension by adapting them using new ideas, In this paper, a two degree of freedom vehicle model is developed incorporating a hydro-pneumatic limited bandwidth active suspension system. The performance goal is to minimize the variance of vehicle body acceleration under inequality constrains imposed on the variance of either tyre deflection or suspension working space. The control gains of this system are obtained using optimal control theory. The performance of the system is evaluated, and compared with a passive system. Finally, the current and future direction of a a hydro-pneumatic limited bandwidth active suspension (4 Hz) research is discussed.