The Effect of Side Impact Collision Delta-V, Restraint Status, and Occupant Position on Injury Outcome

The risk of sustaining injury in side collisions is correlated to collision severity as well as other factors such as restraint usage and occupant position relative to the impact. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2007) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) either between 8:00 and 10:00 or between 2:00 and 4:00, indicating a side impact collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on resultant delta-V, restraint system use, and occupant position relative to the impact. Each body region (head, spine, thorax, abdomen, upper extremity, and lower extremity) was considered separately. Risk of injury for each of these regions was examined based on delta-V which is an indicator of crash severity in the absence of intrusion into the occupant compartment. In general, the data show that when compared to unrestrained occupants, occupants utilizing seatbelts are less likely to sustain AIS 3+ injuries across the body regions examined. Of the occupants considered, 0.23% of near-side occupants and 0.28% of far-side occupants experienced a delta-V greater than 60 kph. Some of the injury patterns investigated for these occupants were not similar to the patterns seen in the 99% of the occupants experiencing less severe collisions. Due to the paucity of data, the relationship between very high delta-Vs and injury risk is not as clear. The NASS-CDS data examined for this study support previous research and show that belted occupants are less likely to sustain AIS 3+ injuries than unrestrained occupants in side impact collisions.