Child Restraint Systems (CRS) with Minor Installation Incompatibilities in Far Side Impacts 2021-01-0915

Side impacts are disproportionately injurious for children compared to other crash directions. Far side impacts allow for substantial translation and rotation of child restraint systems (CRS) because the CRS does not typically interact with any adjacent structures. The goal of this study is to determine whether minor installation incompatibilities between CRS and vehicle seats cause safety issues in far side crashes.

Four non-ideal CRS installation conditions were compared against control conditions having good fit. Two repetitions of each condition were run. The conditions tested were: 1) rear-facing (RF) CRS installed with a pool noodle to create proper recline angle, 2) RF CRS with narrow base, 3) forward-facing (FF) CRS with gap behind back near seat bight (i.e., vehicle seat angle too acute for CRS), 4) FF CRS with gap behind back near top of CRS (i.e., vehicle seat angle too obtuse for CRS). Second row captain’s chairs were set up at 10° anterior of lateral. A sled pulse target of 35 kph and 24 g was used. All trials used the Q3s anthropomorphic test device (ATD) with standard instrumentation. CRS were installed using Lower Anchors and Tethers for CHildren (LATCH).

The non-ideal RF CRS conditions produced kinetic and kinematic outcomes similar to the RF control trials. All RF trials resulted in the ATD’s head rolling toward the direction of impact along the CRS side wing, although upper neck moments were below injury assessment reference values (IARVs). Non-ideal FF CRS conditions also produced outcomes similar to the FF control trials. The top tether load was higher for the “vehicle seat too acute” condition, although the higher top tether loads did not correlate with higher neck forces or HIC36 values in those trials. Overall, the minor CRS/vehicle incompatibilities examined in this study do not appear to affect the performance of the CRS in the far side impact scenario.