Effect of Cargo Loading on Occupant Injury and Seat Deformation in Motor-Vehicle Crashes

Abstract

Purpose: NHTSA studied interior loose objects in the 2000-04 NASS-CDS as part of rulemaking on cargo retention testing in FMVSS 208. This study extends the investigation of cargo and loose interior object loading on occupant injury and seat deformation by cargo in motor-vehicles crashes using NASS-CDS data.Methods: 1996-2011 NASS-CDS was used to investigate the effects of loose interior objects and seat responses on occupant injury in motor vehicle crashes. Crashes were grouped by front, side, rear and rollover. Light vehicles were included with model year 1994+. NASS-CDS added new variables for cargo loading as an injury source and cause for seat deformation in 2007. NASS-CDS electronic cases were analyzed for rear occupants with moderate to severe injury (AIS 2+) from loose objects and MAIS 4+F injury with cargo deforming seats in frontal crashes.Results: There were no AIS 2+ injuries due to cargo loading in the 16 years of NASS-CDS, including specific coding from 2007–11 and by case evaluation in earlier years. In frontal crashes, loose or other interior objects accounted for 250 AIS 2+ injuries in drivers, 32 in front passengers and 206 in 2nd row occupants. The overall rate of AIS 2+ injury was 1.000% for 2nd row occupants due to loose or other interior objects. The individual cases of AIS 2+ injury from loose or other interior objects in 2nd row occupants involved 16 occupants with 44 injuries in frontal crashes. Two cases involved police vehicles and one, an ambulance. In two other cases, the loose interior object was a bike placed in the 3rd row of a station wagon and an unsecured fan in the 2nd row. Each year, there were 540 driver seats deformed by cargo, 438 front-passenger seats and 889 in 2nd row seats. Most cargo deformation of front seats occurred in frontal crashes. Annually, there were 462 driver seats deformed by cargo in frontal crashes, 143 front-passenger seats and 660 in 2nd row seats.Conclusions: This analysis supports NHTSA's earlier conclusion that cargo is not a major source of injury in frontal crashes. While anecdotal cases have been presented in the literature, there were no cases in NASS-CDS. NASS-CDS also showed that when untethered cargo deforms rear seats, it was not related to severe injury to 2nd row occupants.