The National Institute for Occupational Safety and Health (NIOSH) is engaged in research on the effects of whole-body vibration (WBV). The purpose of this research is to quantify the decrement in performance, such as reaction time and continual manual control tracking tasks, caused by WBV. Such decrements may have a bearing on the safety and health of approximately seven million drivers of trucks, buses, tractors, and off-the-road vehicles who are exposed to WBV. To study these effects in the Laboratory, the WBV team at NIOSH has designed and developed a new vibration system. This paper describes the theoretical basis and the main design and construction features of the vibration system for simulating the driver's vibration environment as well as the research possibilities and limits. A hydraulic cylinder and pivoted frame made the concept of a pendulum vibration system a reality. The driver module is designed to simulate a heavy-vehicle driver's environment with a typical control configuration. Depending on the driver's module position this Vibration System can produce vibration in three axes of translation and two of rotation, either singly or mixed.