Case Studies
Seatbelt Claim
A 45 year old male driver of a rebuilt car was hit head on, which resulted in rib and sternum fractures.
We were asked to determine whether he was wearing his seatbelt. We analyzed all the fractures, bruises,
and lacerations he sustained by thorough review of the medical records.
We examined the vehicle interior, including safety restraints, for evidence of occupant loading. In the previous accident this vehicle experienced, the driver's seatbelt had to be cut to extricate the driver, therefore this seatbelt was replaced and was new at the time of this accident. Loading marks were found on the webbing and latch plate of the driver's seatbelt. Since this vehicle had been in a previous frontal accident and the mechanics did not replace the airbag module, it was not equipped with airbags at the time of this accident. We then researched shoulder and lap belt loads in frontal crashes of this vehicle model from published tests using anthropometric crash test dummies. The expected shoulder belt loads seen in the dummy tests were found to be sufficient to cause rib and sternum fractures for an accident of this severity and in this orientation. In addition, a diagnosis of osteoporosis was found in his medical records. This indicates a weakening of the bone throughout the body and indicates that this individual's tolerance to belt loading may have been lower than that of an individual without this condition.
Furthermore, we performed a surrogate study in which we examined the belt routing on a surrogate subject (the same height and weight as the injured individual) in a surrogate vehicle. The belt was found to overlay the locations of the rib fractures, which we digitally reconstructed by compiling CT scans to create a three-dimensional image.
These facts indicated that the individual was wearing his seatbelt. During the impact, he moved forward and into the seatbelt and received his rib and sternum fractures by interaction with the seat belt.