:A PC based interactive program was developed to simulate the unfolding and deploying process of a driver side airbag in the sagittal plane. The airbag was represented by a series of nodes. The maximum allowable stretch was less or equal to one between any two nodes. We assumed that the airbag unfolding was pivoted about folded points. After the completion of the unfolding process the airbag would begin to deploy. During the deploying process, two parameters were used to determine the nodal priority of the inflation. The first parameter was the distance between the instantaneous and final positions of a node. Nodes with longer distances to travel will have to move faster. We also considered the distance between the current nodal position and the gas inlet location. For a node closer to the gas inlet, we assumed that the deploying speed was faster. A graphical procedure was used to calculate the area of the airbag. At each time step, this area was checked against four convergence criteria set up by the user, using an iterative procedure.