A new adaptive damping system. Speed Dependent Damping, has been developed for the 1989 Cadillac Allante' which optimizes ride and handling characteristics under all vehicle conditions. The system has three (3) unique damper settings which are controlled by vehicle speed and brake inputs. The system is comprised of automatically adjustable strut dampers at each corner, a control module complete with diagnostics and associated vehicle wiring. Damping forces are varied through the use of a rotating selector internal to each strut which allows for selective bypass porting. In this manner, ride firmness variation in both the rebound and compression directions is achieved in a deflected disc valving environment. Through objective vehicle and laboratory tests the system has been shown to provide significant gains over a conventional passively damped vehicle.