The Effect of Rear Impact Collision Delta-V and Restraint Status on Injury Outcome

The risk of sustaining injury in rear impact collisions is correlated to collision severity as well as other factors such as restraint usage. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2011) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) between 5:00 and 7:00, indicating a rear 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 and restraint system use. 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. 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 unbelted occupants in rear-end collisions.