Abstract: A vehicle geometry for rollover crush resistance is created by determining a center of mass providing a roll axis and establishing a roof line contact surface spaced from the center of mass by a hoop radius substantially equal to a major radius of roll contact from the roll axis. As a first embodiment, the roof line contact surface is established in original designs for vehicles as a monocoque structure. As a second embodiment, provided as an original equipment manufacture (OEM) item or retrofit structural assembly, an arcuate member shaped as a byte of the hoop radius is employed and is mounted between two side rails with additional structural supports for the arcuate member on a nominally flat roofline.