This paper addresses and traces the influence of several rollover pre-initiation, independent, variables on intermediate and final outcomes, regarding the crashing car/occupant complex system and the resulting casualties. The primary vehicles under investigation are cars. The data for the development of the desired results are extracted from the US field experience of rollover involved cars and car occupants. Six independent variables are addressed in the rollover pre-initiation stage: car travel speed, roadway speed limit, car maneuver, accident precursor, first harmful event, and the location of this event. Five intermediate outcomes are distinguished: the number of quarter turns; loss of passenger compartment integrity through doors that come open in the crash; loss of integrity through disintegrated glazing; occupant ejections, complete or partial; and intrusion of roof, roof borders, and pillars. The final outcomes addressed in the investigation are occupant fatalities, injured survivors, and overall harm. A most informative aspect of this investigation is the comparative evaluation of rollover versus nonrollover crashes. Car travel speed is found to be the source of profound differences. Car travel speed is suggested as a most informative descriptor of “rollover severity,” especially when considered in conjunction with accident precursor and car maneuver conditions that promote lateral speed development.