The Biomechanical Effects of Neck and Back Cushion/Support/Pillow Devices in Low-Speed Rear Impacts

There are numerous commercially available neck and back support/cushion/pillow devices which are oftentimes attached to seats by vehicle owners. To our knowledge, there has been no published research on the biomechanical effects of these devices in low-speed rear impact exposures. In this study, a series of 54 simulated low-speed rear impact tests were conducted using a validated remote-controlled crash sled system. All tests utilized an instrumented rear impact anthropomorphic test device (BioRID II) restrained using a 3-point seatbelt system in a 2018 Toyota Camry LE driver’s seat. Two delta-V ranges were used for the study: a lower range from 7.2 to 8.0 kph (4.5 to 5.0 mph) and a higher range from 10.5 to 11.3 kph (6.5 to 7.0 mph). Six neck only devices, one combination neck and back device, and three back only devices were assessed. Two tests per delta-V range for each device and each device adjustment position were conducted, in addition to control tests without any devices. Analysis and comparison of the biomechanical responses between each neck/back device and the control tests at each delta-V range was conducted. While it wasn’t the case for every device and/or at each delta-V range, the results of this testing showed trends for certain peak biomechanical measures. The following trends were observed for the neck devices: a decrease in head contact forces at the lower delta-V range, an increase in upper neck shear forces at the higher delta-V range, an increase in the upper and lower neck tension forces at both delta-V ranges, an increase in lower neck compression forces at the lower delta-V range, a decrease in the upper and lower neck compression forces at the higher delta-V range, a decrease in the upper neck flexion moment at both delta-V ranges, and a decrease in the lumbar spine flexion moment at the lower delta-V range. The following trends were observed for the back devices: an increase in head contact forces at the higher delta-V range, a decrease in upper neck shear forces at the lower delta-V range, a decrease in lower neck shear at the lower delta-V range, and a decrease in lumbar shear forces at the lower delta-V range.