Repositioning forward-leaning booster-seated child occupants in frontal-oblique low-acceleration impacts

Abstract

Objective: Recently, pre-pretensioner equipped seatbelts (PPT) were found to be effective in repositioning forward-leaning adults. The aim of this study was to evaluate the influence of the PPT on booster-seated forward-leaning children during sled-simulated frontal oblique low-acceleration impacts. Methods: Eight child volunteers (mean: 6.6 ± 0.5 years, four males, four females; weight 24.2 ± 2.1 kg; seated height 64.4 ± 3.9 cm) were seated on a low-acceleration impact sled in a high-back belt-positioning booster seat (BPB) on a rear vehicle bench seat restrained with a three-point seatbelt with a PPT. Volunteers were exposed to a far-side impact 30° from frontal (peak acceleration 1 g, duration 265 ms). Four randomized testing conditions were examined and repeated twice: seatbelt conditions with PPT (85 N at 250 ms prior sled onset) and without PPT; and a standard and a forward-leaning posture. A 3D motion capture system captured participants’ kinematics. Repeated measure three-way ANOVAs tested the effect of seatbelt condition, posture, and repetition on head and trunk peak forward displacement. All displacements were measured relative to the initial position. Results: The PPT reduced peak forward head displacements in both standard (PPT 103 ± 21 mm vs no-PPT 165 ± 19 mm) and forward-leaning (PPT 42 ± 37 mm vs no-PPT 138 ± 25 mm) postures (p