This research provides new insight into the nature, causes and costs of rollover casualties;​ and the economic benefits of basic countermeasures. The National Accident Sampling System (NASS) is a rich source of data on motor vehicle crashes, particularly if one goes beyond the electronic files. In this work, the author reviewed every NASS case from 2002 through 2004 in which a passenger car, SUV, pickup, or minivan that was less than eleven years old rolled over and produced an AIS 3+ injury (more than 500 cases). From this, we developed a useful new classification for these crashes with AIS 3+ injury:​ (1) cases with complete ejections, (2) cases in which there was a head or neck injury from roof crush, (3) other rollovers in which the rollover was the most harmful event, (4) cases in which a collision before the rollover was the most harmful event, and (5) cases in which a collision or major change in elevation during the rollover was the most harmful event. We used the NHTSA “Economic Impact of Motor Vehicle Crashes” and the weighting factor for the crashes to determine the total cost of all of these crash injuries. We then estimated the effectiveness of three simple countermeasures – a strong roof, side window glazing that does not break out during the rollover, and an effective belt use reminder – in reducing the severity and cost of these injuries. The results were most dramatic for SUVs where the discounted potential savings were on the order of several thousand dollars per vehicle over its lifetime. Even for passenger cars, the savings would easily justify the cost of these countermeasures. This work demonstrates the high degree of benefit that would far outweigh the cost of the countermeasures even if the affected vehicles were equipped with electronic stability systems.