SUV Rollover Statistics from the NHTSA

Roof intrusion and roof contact injury are common factors in rollovers. Based upon crash data in NHTSA's National Automotive Sampling System (NASS) for 1995-1999, rollover crashes are the most dangerous collision type for light duty vehicles, measured by the ratios of fatal and serious injuries to the number of occupants involved in tow away crashes. Table 1 shows the ratios and the number of fatalities and serious injuries in light duty vehicle tow away crashes by crash type.

Table 1. Annual Average Number of Fatal and Serious Occupant Injuries in Towaway Crashes by Crash Type in the 1995-1999 NASS and FARS Crash Databases

From NASS, it is estimated that an annual average of 253,000 light vehicle rollovers resulted in towaway crashes. Eighty-one percent (205,000) of these rollovers are in single-vehicle crashes, and 87 percent (178,000) occurred after the vehicle left the roadway. According to the 1999 Fatality Analysis Reporting System (FARS), 10,149 people were killed in light vehicle rollovers. This includes 8,345 occupants who were killed in single-vehicle rollovers. Eighty percent of these people were unrestrained and 64 percent were ejected (including 53 percent who were completely ejected). FARS shows that 55 percent of light vehicle occupant fatalities in single-vehicle crashes involved rollover. The proportion differs greatly by vehicle type: 46 percent of passenger car occupant fatalities in single-vehicle crashes involved rollover, compared to 63 percent for pickup trucks, 60 percent for vans, and 78 percent for multipurpose passenger vehicles. The higher proportion for pickup, vans, and sports utility vehicles may be attributed to their higher center of gravity compared to passenger cars.

An estimated 26,376 vehicle occupants sustain serious or fatal injury due to rollover annually. Over half of these are ejected, and about 13,000 are occupants who remain in the vehicle. In 7,460 cases, at least one injury was due to roof contact, and roof intrusion was present for 6,934 (93%) of those. Over half (3,734) of those sustaining injury with the occurrence of roof intrusion were belted. Thus, roof crush intrusion is estimated to occur, and potentially contribute to serious or fatal occupant injury, in about 26% (6,934/26,376) of the rollover crashes.

Other meaningful findings showed that vertical roof intrusion was present in a larger percentage of pickups (12.9%) and sport utility vehicles (13.7%) than in passenger cars (6.3%) in towaway crashes.

According to NASS, roof contact and the severity of rollover injury is greatly influenced by belt usage. Eighty-nine percent of unbelted ejected occupants receive their most severe injury from ejection (based on NASS annual averages from 1988-1997). Consequently, preventing ejection is the most important means for reducing injury to unbelted occupants. Roof crush intrusion is an additional injury source for unbelted occupants, although generally only a minor contributor. Roof intrusion is present in the majority of cases, but is only the leading cause of injury in less than 10 percent of unbelted rollover cases.

In summary, unbelted occupants in rollover crashes are primarily injured by ejection from the vehicle, which is fatal in about half the cases. Belted occupants in rollover crashes are primarily injured by roof contact and by contacts with other components within the vehicle's interior. Roof contact for belted occupants in rollover crashes is usually non-fatal, but the severity of the injury is only directly related to the level of roof intrusion in severe cases of intrusion. In less severe cases, the severity of injury is related to other vehicle and occupant factors. A discussion of the relationship between these factors and injury severity is presented in the following section.