Assessing Child Belt Fit, Volume 1: Effects of Vehicle Seat and Belt Geometry on Belt Fit for Children with and without Belt Positioning Booster Seats

摘要

A laboratory study was conducted to quantify the effects of belt-positioning boosters on lap and shoulder belt fit. Postures and belt fit were measured for forty-four boys and girls ages 5 to 12 in four highback boosters, one backless booster, and on a vehicle seat without a booster. Belt anchorage locations were varied over a wide range. Seat cushion angle, seat back angle, and seat cushion length were varied in the no-booster conditions. All boosters produced better mean lap belt fit than was observed in the no-booster condition, but the differences among boosters were relatively large. The belt fit was measured in each test condition using the 6YO and 10YO Hybrid-III ATDs. ATD belt fit was strongly correlated with child belt fit across test conditions, but offsets between the ATD and child belt fit scores were observed due to anatomical and postural differences between the ATDs and children. The results of this study have broad applicability toward the improvement of occupant restraints for children. The data show substantial effects of booster design on belt fit, particularly the effects of alternative lap and torso belt routing approaches. Regression analyses quantify the critical importance of belt anchorage location for child belt fit, providing an important foundation for efforts to optimize belt geometry for children. The strong correlation between ATD and child belt fit scores means that ATD-based measurements can reliably be used to assess booster and vehicle designs with respect to child belt fit.