Age-based Selection of Child Restraints

Abstract

Background: Advice to parents about child restraints is sometimes based on the child’s weight, and can be complicated and confusing. Children tend to want to progress to the next restraint earlier rather than later, and the lack of clarity in advice to parents means that parents are more likely to move children up into the next type of restraint prematurely. Moreover, many parents do not know the weight of their child. This paper explores what might be the consequences of very simple advice, such as advising parents to change the type of restraint when children reach 6 months of age, 4 years, and 8 years. Method: The distribution of children’s weights at different ages is used, along with the range of weights for which each restraint is appropriate, to work out the number of children who would be in an inappropriate restraint if progression were at particular ages. Results: If 6 months is the age of transition from an infant capsule to a forward-facing child restraint, the number of children misclassified is approximately two one-month cohorts. If 48 months is the age of transition from a forward-facing child restraint to a booster seat, the number of children misclassified is again approximately two one-month cohorts. Conclusion: These numbers of misclassifications are low (relative to what has been reported in surveys when weight-based advice was the norm). It has not been proven that there would indeed be good compliance with sharp ages of transition, but the simplicity and salience of age make it attractive as a criterion.