A rollover is a crash in which the vehicle revolves at least one-quarter turn, regardless of whether the vehicle ends up laying on its side, roof or even returning upright on all four wheels. Rollovers occur in multiple ways. Most rollovers are "tripped," that is the vehicle rolls over after leaving the roadway striking a curb, soft shoulder, guardrail, or other object that "trips" it. A small percentage of rollovers are caused by events are "untripped" and caused by tire defects. Rollover crashes are infrequent, but dangerous events. The 2001 Fatality Analysis Reporting Systems (FARS) tells us that over 10,000 individuals were killed as occupants of light vehicles in rollover crashes. Of those, about 8,400 were killed in single-vehicle rollover crashes. Rollovers in SUVs are the leading cause of severe injury and death to their occupants. Likewise, rollovers are the leading cause of death to pickup truck occupants.

More than 10,000 people a year are killed in rollovers. The best way to prevent the deaths is to keep vehicles from rolling over in the first place. Electronic stability control is significantly reducing rollovers, especially fatal single-vehicle ones. When vehicles do roll, side curtain airbags help protect the people inside, and belt use is essential. However, for these safety technologies to be most effective, the roof must be able to maintain the occupant survival space when it hits the ground during a rollover. Stronger roofs crush less, reducing the risk that people will be injured by contact with the roof itself. Stronger roofs also can prevent occupants, especially those who aren't using safety belts, from being ejected through windows, windshields, or doors that have broken or opened because the roof has deformed.

Overturf v. Ford Motor Company and Bridgestone Firestone, Inc.