Injury Patterns in Motor-Vehicle Crashes in the United States: 1998-2014

The NASS-CDS database for years 1998-2014 was analyzed to examine trends in injury patterns. To account for changes in data collection for years 2009 and later, most analyses focused on occupants in vehicles newer than 10 years relative to the given crash year. However, for analysis of trends by crash year, the number of occupants injured in older vehicle was estimated. The number of occupants with AIS2+ or AIS3+ injuries was assessed by main crash type (rollover, frontal, rear, near-side, and far-side) and AIS body region (head, face, neck, thorax, spine, abdomen, upper extremity and lower extremity). Risk of AIS2+ or AIS3+ injury was also calculated. Dependent variables include occupant age, BMI, gender, occupant seating position, and restraint; vehicle type and model year; plus crash year. Additional analyses were performed to determine if injury patterns varied within body region. Overall trends in injury indicate a substantial drop in the total number of injuries since 1999. Risk has dropped consistently for near- and far-side crashes, but not for rollovers, frontal, or rear impacts. For AIS3+ injured occupants, the 16% of occupants who are unbelted make up between 45-55% of injured occupants in all crash types except for near-side. Rear occupants have a 1.7 times greater risk of AIS2+ injury in far-side impacts and 2.2 times greater risk in rear impacts compared to front seat occupants, but front occupants have 1.5 times greater risk than rear occupants in frontal crashes. The risk of AIS2+ and AIS3+ injury to all body regions generally increase with age. The proportion of AIS2+ and AIS3+ injured occupants in rollovers decreases with age. In frontal, near-side, and far-side crashes, occupants with AIS2+ injury aged 66 and greater make up a higher proportion of the injured occupants compared to their involvement crashes. Risk of AIS3+ injury is highest in pickup trucks for frontal crashes, near-side and rear crashes and in passenger cars for far-side and rollovers. Risk of AIS2+ and AIS3+ injury is highest in pickup trucks for all AIS body regions. Risk of AIS3+ injury to the pelvis and femur have dropped substantially since vehicle model years 1999-2004.