This paper deals with the synthesis of control laws for quarter car 2-DOF models with various suspensions. The control strategies to determine controllers (actuator, damping coefficient, or spring stiffness) are derived and proved by optimal control theories. The performances of semi-active suspensions with preview control show more jerk in spite of less acceleration, which means that ride comfort is not practically improved. The controllers determined by minimizing the performance indices including jerk RMS term improve ride comfort safely. The simulation for the preview control of active suspension considering jerk shows better frequency charateristics of body acceleration and tire deflection simultaneously. The performances of active and semi-active systems are compared to those of systems disregarding jerk and analyzed in time domain by numerical simulation.