The Effect of Active and Conventional Head Restraints on Front Seat Occupant Responses in 16 km/h Rear Impacts 2020-01-1217
This study assesses front seat occupant responses in rear
impacts with active head restraints (AHR) and conventional head
restraints (CHR) using field accident data and test data from the
Insurance Institute for Highway Safety (IIHS). 2003-2015 NASS-CDS
data were analyzed to determine the injury rate in 1997+ model year
seats equipped with AHR and CHR. Results indicated that only 3.1%
of occupants were in seats equipped with AHR. More than 58% of
occupants were uninjured, irrespective of AHR presence. In <24
km/h delta-V crashes, AHRs were 35.6% effective in reducing MAIS
1-2 injury overall and 26.4% in reducing MAIS 1-2 cervical injury.
In IIHS 16 km/h rear sled tests, an instrumented BioRID was
evaluated on seats with AHR and CHR. The biomechanical responses
were analyzed. HIC15 and concussion risk were calculated from head
acceleration data. Test data with AHR and CHR were matched by make
and model. First, older model seats with CHR were compared to
models with AHR. Then, the models with AHR were compared to newer
models with CHR. These analyses showed a reduction in head and
upper neck responses with AHR compared to prior generation CHR. A
further reduction in these responses was observed in newer CHR
compared to prior model AHR. Time at head contact was 89.1 ±13.7 ms
with older CHR, 62.4 ± 8.7 ms with AHR and 60.6 ± 9.0 ms with newer
CHR. The contact duration was however longer with the AHR tests.
The average seatback deflection was 13.6 ± 3.6 degrees with older
CHR, 12.3 ± 3.0 degrees with AHR and 10.4 ± 3.0 degrees with newer
CHR. Similar trends of decreasing concussion risk were observed.
However, the risk of concussion was negligible with later models.
The results from this study underline continuous improvement in
injury mitigation, regardless of head restraint design.
Chantal Parenteau, Ian C. Campbell, Stephanie A. Pasquesi