Interactions between rearward-facing child restraint systems and the front row seatback in frontal impact sled tests

Abstract

Objective

Some child restraint system (CRS) manufacturers specify a minimum distance between the CRS and the seatback, whereas others require that the CRS may contact the seatback but cannot be “braced”; however, few studies have investigated these interactions. Therefore, the aim was to investigate the interactions between the front row seat and rearward-facing CRS models with and without a support leg during frontal crashes.

Methods

Sled tests using the FMVSS 213 frontal crash pulse were performed with the Q1.5 and Q3 anthropomorphic test devices (ATDs) seated in rearward-facing infant and convertible CRS models, respectively. A front row vehicle seat was in front of the test bench in three track positions: brace, touch and gap. For the touch condition, the front row seat was translated aftward until the seatback contacted the CRS. For the brace condition, the front row seat was translated 20 mm aftward. For the gap condition, the front row seat was translated 50 mm forward. Each condition was tested with and without the support leg of the CRS.

Results

The tests with a support leg were associated with significantly (p = 0.007) lower resultant linear head acceleration 3 ms clip compared to the tests without a support leg, but the reduction of head injury criterion 15 ms (HIC15) was not significant (p = 0.057). The Q1.5 ATD in the rearward-facing infant CRS with a support leg had the lowest injury metrics for the touch and gap conditions, whereas the Q3 in the rearward-facing convertible CRS had the lowest head injury metrics for the brace condition.

Conclusions

The use of a support leg provided a clear benefit in terms of reducing head injury metrics for the Q1.5 in the rearward-facing infant CRS, especially for the touch and gap conditions. The rearward-facing convertible CRS in the current study appears to benefit from being braced against the front row seat. However, further tests are required to allow further statistical comparisons and determine if these preliminary findings extend to other rearward-facing CRS models.

Keywords:

• ATD
• CRS
• head injury

Acknowledgments

The authors would like to acknowledge the National Science Foundation (NSF)-founded Center for Child Injury Prevention Studies (CChIPS) at Children’s Hospital of Philadelphia (CHOP) and Ohio State University (OSU) for sponsoring this study and its Industry Advisory Board (IAB) members for their support, valuable input and advice. The views presented are those of the authors and not necessarily the views of the NSF, CChIPS, CHOP, OSU and/or the IAB members. The authors would like to acknowledge the support of the CChIPS administrative team, especially program manager Lindsey Mitros. Sled tests were conducted at Calspan (Buffalo, NY) and the authors would like to acknowledge the assistance of Bill Horn, Jon Gondek, Daniel Wells and Matt Boczar.

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

This research was funded by CChIPS at CHOP and OSU.