In a mild roll-over the vehicle may fall onto its side on a flat surface but will continue to roll if?

In a mild roll-over, the vehicle may initially tip onto its side but will continue to roll if the center of gravity shifts significantly due to the momentum and angle of the roll. If the vehicle's wheels lose contact with the ground or if there's enough lateral force, it can lead to further rotation. The design and height of the vehicle also play a role in determining how easily it rolls over.