The objective of this study is to determine whether gross passenger car characteristics are associated with the frequency of vehicle rollover. The characteristics examined are vehicle weight, track width, and vehicle height.

Data used in the study are drawn from two states participating in the ACIR program and represent all accidents, property damage as well as injury, investigated by the state police for a period of one year. Data from each state are examined independently and results are then compared.

The data indicate that there is a strong correlation between rollover frequency and vehicle dimensions:​ rollover increases as car size shifts from heavy, wide track, low vehicles to light, narrow track, high cars. Car weight and tread width appear to have the greatest influence on vehicle overturn.

To understand fully all of the implications of the observed vehicle behavior, it is suggested that further study combining analysis of accident data, computer simulation, and actual rollover tests be conducted.