Using vehicle damage and scene evidence to understand mechanisms of injury in rollover crashes
Rollover crashes often lead to severe and catastrophic injuries. Injury risks arise mainly from from roof intrusion, from full or partial ejection and hard contact with the interior of the vehicle. Identifying the cause of the rollover, pre-crash speeds and the mechanisms of injury can be challenging but important to to the determination of liability.
The reconstruction of rollover crashes requires consideration of scene evidence, exterior vehicle damage, interior damage, and details of injuries. We can use this evidence to describe the way in which the forces evolve during the crash, between the vehicle and the ground and the occupants with the vehicle interior. hence we are able to correlate vehicle damage with the rollover sequence and hence to understand occupant loads and kinematics, including forces causing ejection and the timing of relevant events.
Correlating scene evidence with vehicle damage can be used to reconstruct the rollover sequence. In this case, overlaying vehicle rotation on a scene diagram provided information that was sufficient to reconstruct the roll. Associated debris was then used to identify the point of ejection for the injured occupant.
Occupant kinematics during these events are governed by the same physical processes as other crash types: the collision between the occupant and the interior can leave clear impressions on the interior surfaces, and large deformations are often associated with specific injuries.
In this case, an unrestrained occupant struck the interior of the door at high speed during ground contact during the rollover. The forces were maintained for long enough to push the window frame out of the door frame so that is was caught by the ground on the next roll, causing the severe deformation of the frame that is visible in the photograph
Although rollover crashes appear chaotic, the discreet events in a rollover do have structure. The roll of restraints in injury prevention are likewise well understood. Our understanding of these crashes and our experience in evaluating post-collision evidence provides allows us to provide reliable opinions in such cases.