Abstract
A method of spectrum analysis of multi-input system has been used to obtain the response function of passenger cars receiving a gust of wind and steered under general driving conditions. Some examples were shown, after which the conclusion was made that various response functions of steering input and wind force necessary for the evaluation of control and stability of an automobile are obtainable at once. In this regard, it is possible to calculate various response functions under actual driving conditions so that the spectrum analysis will serve an important role in the study of control and stability of automobiles in future.