Near and Far-Side Adult Front Passenger Kinematics in a Vehicle Rollover

Abstract

In this study, U.S. accident data was analyzed to determine interior contacts and injuries for front-seated occupants in rollovers. The injury distribution for belted and unbelted, non-ejected drivers and right front passengers (RFP) was assessed for single-event accidents where the leading side of the vehicle rollover was either on the driver or passenger door. Drivers in a roll-left and RFP in roll-right rollovers were defined as near-side occupants, while drivers in roll-right and RFP in roll-left rollovers were defined as far-side occupants. Serious injuries (AIS 3+) were most common to the head and thorax for both the near and far-side occupants. However, serious spinal injuries were more frequent for the far-side occupants, where the source was most often coded as roof, windshield and interior. Based on the injury sources for both situations, head injuries seem to occur from contact with the roof, windshield (in particular for unbelted occupants) and pillars, while thoracic injuries resulted from contact with steering assembly and the interior. The field injury data was compared with the Hybrid III responses obtained from simulated mathematical rollovers to better understand occupant kinematics and injury biomechanics. These simulations were validated using laboratory tests. The laboratory tests included the FMVSS 208 dolly rollover, the ADAC corkscrew, curb and soil-trips, bounce-overs and fall-overs. Based on the mathematical simulations, the kinematics of the front far-side occupant differed from that of the near-side. For the belted far-side occupant, the torso often slipped out of the belt which allows excursion towards the near-side occupant. For the belted nearside occupant, the shoulder belt remained on the upper body during the initial roll phase. The occupant nonetheless moved up and outwards and the head could contact the roof-rail and header areas depending on the rollover condition simulated. The near-side occupant's head crossed the window plane more frequently than the head of the far-side occupant. Dummy kinematics from the simulation help explain the frequency of serious head and thorax injuries reported in the field. Field data analysis and mathematical simulations are useful in understanding injury biomechanics and providing guidance for future testing.