Forensic evidence within a crash vehicle's occupant compartment as well as the occupant injuries may provide important validation tools for the accident reconstructionist, particularly to corroborate the principal direction of force (PDOF) on the occupant. The objective of this study was to evaluate forensic evidence of dynamic loading found on the seat belt webbing, latch plate, D-ring, and any other associated restraint components as a function of frontal impact angle in a series of sled tests utilizing 95th percentile male, 5th percentile female, and 6 year old Hybrid III ATDs.
A late 1990s full size SUV was converted to a sled buck for testing. The test series included impact angles from 0 degrees to 60 degrees in 15 degree increments. The tests were conducted at approximately 35 kph (22 mph) on a rebound style sled. Post-impact, the seat belt systems were removed from the sled, labeled and archived for subsequent detailed analysis. Physical evidence for each belt assembly was documented using macroscopic and photographic techniques.
The results in this study indicate the occupant PDOF can be confirmed by examining the safety belt systems, but that the evidence alone cannot qualitatively determine the occupant or crash PDOF. The forensic evidence can be used as a validation tool as related to the calculated PDOF.