Booster seats are recommended for children who weigh 15 kilos and upwards until they reach a weight in excess of 36 kilos. The main purpose of these booster seats is to serve as an intermediary step between a child restraint system with a harness, like the ones in Groups 0 to 1, and using the car's seat belt.
Using booster seats enables the seat belt to fit properly over the child's body, thus avoiding potential injuries as a result of the belt being positioned incorrectly. This article is specifically dedicated to reviewing the benefits of restraint systems and the correct positioning of the attachment points.
But what would happen if a child that still needs a booster cushion were to travel without one, despite it being a compulsory requirement? The answer can be found in one of the presentations given at the latest International Conference Protection of Children in Cars held in Munich, specifically the one based on the work of Pitcher, Robinson and Baig, under the title “Are booster child restraints effective at protecting older children?” There was one section in which the consequences of not using them was discussed.
The danger presented by a badly adjusted seat belt
A seat belt must be properly positioned in order to be effective. We have already said this many times: the upper part of the strap should rest on the shoulder, while the lower part should support the pelvis, fitting snugly over the legs and pelvis and not over the abdomen.
If a child is still less than 140 or 150 cm tall (the regulation specifies 135 cm, but it is always recommendable to wait a little longer just in case), the seat belt will not fit snugly to the body in the following situations:
- If the shoulder strap is too close to the neck, that area could sustain injuries in the event of a collision.
- If the upper strap is too far away from the shoulder towards the arm, the torso will not be held in place by the belt, increasing the risk of the head striking another part of the car.
- In the event of the belt passing underneath the arm, the child is only then supported by the abdominal strap which increases the pressure on that area, in addition to the situation described in the last point.
If we then consider the poor positioning of the lower or pelvic strap, the consequences can be different. At the moment of impact in a collision, the pelvis tends to be thrown forward until the lower strap starts to slow the momentum down, meaning that, if it is badly fitted:
- Should the strap slide up to the abdomen, the risk of sustaining abdominal injuries is multiplied. This can also happen if the child is slim or if the seat belt has been incorrectly adjusted, or if there are no lower strap guides.
- Another potential consequence of a badly positioned pelvic strap is the occurrence of the submarining effect: The child slides underneath the lower strap at the moment of impact, with a high probability of sustaining abdominal injuries.
It is due to all of these potential consequences that the use of booster seats is recommended even for children taller than 135 cm if it helps to better adjust the seat belt. Even though that height is the legal minimum for being able to use a seat belt, it is prudent to wait until children reach 150 cm, so that the seat belt can be better adapted to the child's physical features.