The objective of this study is to develop a control law of the active suspension for the safety and ride quality improvement using a frequency and time-mixed shape performance index with speed and road-adaptive preview logic. The incorporation of a mixed shape performance index allows one to emphasize or de-emphasize certain variables over specific bands of frequencies. The criteria recommended by ISO2631 and BS6841 provide the frequency weighting curves for human body vibration in relation to ride comfort. A unified strategy of finite optimal feedforward control is developed both for a haversine bump and general highway. In the course of deriving the feedforward control logic, we used the theorem that approximate control solution exists and becomes arbitrarily close to the optimal control solution for a sufficiently large preview time. Through an eight degrees of freedom Linear ride model, we show that preview information and complex type performance index can improve the ride quality of the vehicle.