An on‐road driving study comprising six children aged 8‐13 years (138‐150 cm) was conducted to increase the understanding of children’s natural sitting behavior during a car ride. Each child was video recorded during a pre‐determined 40‐minute route in the rear seat of a modern car. The route was taken twice;​ once when the child was restrained using a backless booster and once when the child used the seat belt only.

The children spent most of their riding time in a sitting posture with their upper back and shoulders in contact with the seat back, independent of using a booster or not. Slouched sitting postures were predominantly seen when restrained by the seat belt only, but in one case also when using the booster. The booster helped to position the belt at mid shoulder. In the slouched sitting posture, the booster helped to guide the lap belt below the abdomen. Also, the booster helped to keep the children in a more stable lateral sitting posture.

The study provides details on sitting behavior of children in the transition age for booster use adding valuable knowledge for future safety system improvements. It also takes into account comfort issues.