To the Editor: The Australian Transport Council should be commended for approving the National Transport Commission’s revised road rules for the safety of children in motor vehicles.1 A key requirement is that children aged 4–7 years are to be restrained in an approved forward-facing child restraint or booster seat. It is expected that such changes, once enacted by states and territory governments, will result in fewer children being injured and killed.

In a letter in the 4 August issue of the Journal, Zurynski and colleagues argued that these changes will bring Australian rules closer to — but nevertheless fall short of — overseas jurisdictions, where children up to 12 years of age or 145 cm in height must be restrained in booster seats.2 Notably, a wider selection of booster seats is available in these jurisdictions, including seats suitable for children weighing up to 36 kg. In contrast, the Australian/New Zealand Child Restraint Standard (AS/NZ 1754) stipulates that an “approved booster seat” is one that has a maximum design weight threshold of 26 kg.3 Mandatory consumer information notes that booster seats are “to be used only with lap-sash seatbelt or with a seatbelt and child harness for a child weighing from 14–26 kg”, and that they are not to be used if the child’s eye level is above the top of the booster back, or above the top of the car seat back or headrest when restrained in the booster seat.3

The matter of children exceeding the maximum weight threshold of 26 kg while failing to meet the transition height to adult seatbelts is far from trivial. Previous research published in the Journal found that about 50% of 7-year-olds whose height fell between 100 cm (the upper recommended height for child car seats) and 145 cm (the recommended seatbelt transition height) exceeded 26 kg, with only 27% having an age- and sex-adjusted body mass index > 25 kg/m2.4 Consequently, due to the current range of approved booster seats available in Australia, children may be placed at some unquantified risk in the event of a crash, as optimal protection above this weight threshold cannot be guaranteed. Further compounding this scenario is that pursuant to r266 of the Australian Road Rules, if a child “cannot safely be restrained as required . . . because of his or her height or weight”, the use of a seatbelt may be deemed acceptable.1 To avoid this scenario, it is essential that booster seats with a higher maximum weight threshold be made available in Australia as soon as practicable.