The Problem:

 About 10,000 Americans die every year in rollover accidents, many more are seriously injured. Most of these deaths and serious injuries are due directly or indirectly to roof crush.

 Roof crush causes injury both directly and indirectly, chiefly in the latter case by promoting occupant ejection. Ejected occupants can hit the pavement hard or have the vehicle roll over on them. The roll of roof crush in direct injury causation is a little more complicated, but it essentially involves what is in effect high speed contact with the ground when the roof fails.

 While SUVs and 4 x 4s are more likely to rollover than most other light vehicles, any vehicle can rollover under the right circumstances. So, weak roofs which allow extensive roof crush are a problem for almost all highway vehicle occupants.