A controlled matched pair comparison of child ATD responses, installed in different models of child restraints was conducted to investigate differences between the current CMVSS 213 bench and the proposed FMVSS 213 bench. The effect of acceleration and deceleration pulses on ATD responses were also examined.

The CRABI 12-month-old and the Hybrid III 6-year-old were placed in rear facing and forward-facing child restraints installed on the current CMVSS 213 bench and the proposed FMVSS 213 bench. Repeatability of installation was verified with a 3D Faro measurement system. A total of 114 tests were conducted on the Seattle Safety acceleration sled and on the Messring HydroBrake deceleration sled.

Head, chest and pelvis acceleration responses were compared for pairs matched as a function of ATD, seat type, and installation method. Maximum head excursion, maximum knee excursion, and seat excursion at the time of maximum head excursion were estimated using video recordings.

Downward displacement of rear facing seats was reduced on the proposed bench when compared to the current CMVSS 213 bench. The Hybrid III 6-year-old head, chest, and pelvis responses on the two benches were similar (difference of ≤ 5g). One forward facing seat exhibited a higher chest response on the proposed bench. Maximum head excursions relative to both the bench and the seat tended to be greater on the proposed bench for all seats regardless of installation method. Paired responses on the acceleration and deceleration sleds were similar. Differences in paired responses were found to be more strongly linked to product design characteristics than to test bench characteristics or sled type.

The study contributes to an understanding of the influence of test configuration and is pertinent to the development of child restraint regulations or consumer evaluation programs.