The CVS/ATB (Crash Victim Simulator/ Articulated Total Body) computer program solves the equations of motion in three dimensional space for a set of rigid bodies connected by joints. The program permits the specification of contact interaction properties between the rigid bodies and the surrounding environment. It is, therefore, possible to specify initial conditions of motion for the rigid bodies, and calculate the subsequent motion resulting from the forces imposed by the environment.The program is sufficiently general that it can be applied to a wide range of physical dynamic situations. However, the principal motivation for its development was to evaluate the interactions of the human body with the environment inside a motor vehicle during a crash. Subsequently, it has been applied to a number of other dynamic simulations including pedestrian to vehicle impacts and the emergency escape of air crew from aircraft.The CVS/ATB program is in the public domain. The most recent documentation was published in 1982, and is available from the National Technical Information Service (NTIS). Since the 1982 documentation was published, a number of improvements have been made. These include additional options for specifying the characteristics of the human body, the motion of the vehicle, and the interaction between the two. In addition, test procedures for producing the needed input data have been developed, and a significant amount of data has been produced and published. Finally, auxiliary programs to produce input data for the model are now available. The sources of these improvements are summarized in the paper.