Q‐Series dummies, combined with hip liners and Abdominal pressure twin sensors have shown limited capacity to discriminate differences in child booster seats. They offer little incentive, therefore, to optimise lap belt path. Anterior‐superior iliac spine load cells measure force (Fx) and moment (My) at each ilium. They measure dummy‐belt interaction in the lower region of, and below, the abdominal pressure twin sensors. This study investigated whether anterior‐superior iliac spine load cells (compared with the abdominal pressure twin sensors) are sensitive to the position of the belt over the pelvis, and whether they have potential to predict booster seat performance.

Both sensors detected poor restraint in extreme cases with clear submarining. However, neither sensor fully distinguished undesirable belt interactions in which submarining was unclear (albeit suspected in some cases). This possibly reflected the dummy’s capacity to display full submarining. Although significant pelvic displacement (with reclined torso) was observed, the belt may have stayed on the iliac crests. The anterior‐ superior iliac spine load cells offered complimentary information to the abdominal pressure twin sensors, but essentially duplicated their findings in our experiments. Characterising their response in a larger programme of experiments would help interpret their output and/or develop robust metrics. Nevertheless, measuring anterior‐superior iliac spine loads has the potential to encourage booster designs that keep the belt low on the pelvis.