<div class="htmlview paragraph">An attempt is made to describe the stability of vehicles on very rough terrain that may have large slopes. The basic premise of the paper is that the theory of ship stability is more applicable to problems of this kind than the traditional on-read vehicle stability theories. The linear theory is discussed as is driving on a rough slope, pitching, vertical oscillations and large angles. The methods of catastrophe theory as presented originally by Zeeman are used in an attempt to explain the behavior of the off-road vehicles.</div>