In recent years, more importance has been attached to the collision safety performance, and in the United States installation of an airbag in the passenger cars has already been enforced by law. At the same time, it is becoming obligatory to install airbags in recreational vehicles (hereafter called RV). Under these circumstances, ISUZU has also been undertaking development to install airbags in the cars it produces, while conducting research on simulation of the airbags. In this report, we would first like to ensure that the simulation can reproduce the conditions of a sled test and then illustrate the case in which the simulation was applied in order to obtain the optimum specification of the collapse characteristic of the steering column which becomes more important as a restraint system when an airbag is installed In order to efficiently introduce the optimum system of airbags in RV, we are making attempts to develop and utilize this simulation technique.