John R. Yannaccone, P.E., Principal Mechanical Engineer

Case Summary: A package delivery vehicle, with a driver and supervisor, was stopped in the roadway due to a prior traffic incident obstructing the travel lane. While stopped, the delivery vehicle was impacted from behind by a large dump truck pulling a trailer. The impact pushed the delivery vehicle forward causing it to tip onto the driver’s side. The police report indicated all occupants were wearing lap and shoulder seatbelts at the time of the crash. The delivery vehicle driver was found restrained in his seat and complained of back pain. The right-front occupant was found in the cargo area of the vehicle. He sustained a large scalp laceration and numerous soft tissue injuries. He also had a stable spinal fracture and a shoulder separation.

Analysis: The vehicle was inspected, and it showed heavy rear damage from the impact by the dump truck. The driver’s seat was a typical, floor-mounted seat with a standard lap and shoulder belt. While the driver’s seat was impacted from behind by the bulkhead and pushed forward by the package shelves, due to the rear intrusion, the driver’s occupant space was generally well-preserved. In contrast, the right-front seat was a fold-down seat mounted to the bulkhead separating the occupant space from the cargo space. This bulkhead was found separated from the vehicle and lying in the cargo area. Both seatbelts in the delivery vehicle had heavy signs of loading, consistent with being in use during the crash.

While the design of the right-front seat would not have provided the best occupant protection, any ability it had was greatly compromised when the bulkhead on which it was mounted separated from the vehicle structure. The bulkhead itself was attached to the vehicle with various fasteners; however, the design clearly focused on the ability to carry the occupant loads in a frontal impact, not a rear impact to the vehicle. In this crash, the fasteners failed in numerous ways, allowing the bulkhead to completely detach from the vehicle. During the crash, the right-front occupant remained seatbelted in his seat, attached to the bulkhead, as it moved rearward into the cargo area where he was seriously injured. Had the bulkhead been better attached to the structure of the vehicle, it would have remained in place and the passenger would have been supported by the bulkhead and not entered the cargo area of the van. This would have eliminated his exposure to many of the hazards which were associated with his injuries, and it is expected he would have sustained recoverable injuries similar to the driver. It was shown that the design and construction of the van were a significant factor in the severity of the injuries to the passenger.

Result: The case resolved with all defendants prior to trial.

John R. Yannaccone, P.E., Principal Mechanical Engineer with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

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