Numerous heavy industrial vehicle types, extended driving hours, and exposure to severe working environments are transportation-related factors in industry and agriculture. The increased number of these vehicles inevitably results in increased demand for improved ride comfort. The ride vibration detected at the driver’s seat signi„cantly in™uences driver fatigue and safety. In fact, the ride vibration levels of commercial vehicles are 9 to 16 times higher than those of passenger cars, and most commercial vehicle drivers are exposed to this ride vibration for 10 to 20 hours a day [1]. Although ride comfort improvements have been attempted through appropriate tires and primary and secondary (cabin) suspensions, commercial vehicle drivers still suffer from the effects of low-frequency and high-amplitude ride vibration.