Light-Vehicle Occupancy and Severe Injury by Vehicle and Crash Type

Abstract

Purpose: This study investigated the number of occupants involved and severely injured in light-vehicle crashes by vehicle and crash type. Methods: 1994–2010 NASS-CDS data were analyzed to estimate the risk of severely injured occupants involved in motor vehicle crashes. Crashes were grouped by front, side, rear, and rollovers. The effect of occupancy and vehicle type was investigated. Light vehicles were less than 4536 kg with model year 1994+. The annual number of Maximum Abbreviated Injury Scale (MAIS) 4+F injuries was estimated and the risk was determined using all occupants with known injury (MAIS 0–6+F). Results: There were 21,869 MAIS 4+F injuries annually, with 62.7 percent involving passenger cars, 15.9 percent sport utility vehicles (SUVs), 15.3 percent trucks, and 6.1 percent vans. In 36.6 percent of van crashes, MAIS 4+F occurred when there were 4+ occupants and 13.0 percent with 7+ occupants in the vehicle. Overall, 12.8 percent of severely injured were in crashes involving 4+ occupants and 1.4 percent with 7+ occupants. In addition, 30.1 percent of MAIS 4+F occurred in rollovers and only 5.8 percent of crashes were rollovers. Rollovers had the highest injury risks, irrespective of the number of occupants. There was a trend for an increased fraction of injury in frontal crashes and a lower fraction in rollovers. There were high risks in side and rear crashes with 5+ occupants. Conclusions: On average, there were 1.35 occupants involved in a crash per vehicle. Severely injured occupants were uncommon in 5+ occupancy vehicles. There was a trend for increased injury risks with occupancy. The risk was 1.65 times higher in vehicles with 7+ occupants compared to those with a driver only.