Girl TORQUE: Child safety seats

New Zealand doesn’t have one standard, and accepts seats from all over. So working out what’s best, or indeed what fits best, can be confusing.

Child weights are often quoted, but you only need to look around at the supermarket to see how kids vary in size. Some two-year-olds are as heavy as their five-year-old neighbour, yet their proportions are very different – and they need different seats to best protect them.

Is the seat dangerous if your child gains weight to just above its stated recommendation? Probably not – but stepping up to one suited to an older child might mean the apple of your eye isn’t best protected. And how would you know? It’s giving me a headache just thinking about it…

A chat to professor Lynne Bilston, a senior research fellow based at the Prince of Wales Medical Research Institute in Sydney, and here as a guest of Plunket, suggests it could soon get easier.

For changes have been made to the latest NZ-Australian standards – AS/NZS 1754 and 3629 – that will remove weight guidelines from child seats which comply, and instead refer to height. Easier still, there will be height labels on the seats themselves. Working out if you’re buying the right one is as easy as sitting your child in the seat, in the shop.

Lynne does applied research into car crash injury, especially in children. She’s a mum, and she’s convinced that categorizing seats by child weight is “loco” and results in many children “being transitioned too early”.

“Many parents think their child is too big for a seat before they are, especially with rear-facing when parents think that as soon as the foot hits the end of the seat they should move on.”

She’s found that overlapping weight ranges in different seat types encourages early change.

She points out young children are not only proportioned differently to older ones, their internal organs are less developed – and less protected. For example a child has a softer ribcage than an adult, which is why child seats use multiple straps to spread the load.

Her ideal is to make it easy to identify which seat your child should use. The new Australia-NZ standards use colour-coded belt paths so it’s easier to check the seatbelts holding the seat are correctly sited. They introduce a new class of bigger booster seats, for larger kids, while booster cushions (as opposed to those with side wings) are removed from the standard.

And there will be shoulder-height labels on each seat indicating the shortest and tallest height for which the seat is designed.

Surveying in malls, her team discovered that using height labels as part of the seat design increased the odds a parent would select the correct restraint by 4.7 times.

Bilston’s goals next time around are boosters for children aged four to 10; a seat design shaped to ensure three will fit across a Corolla-sized car while leaving the buckles accessible; postural support for a sleeping child; and better head protection from side impacts.

She’d still like to see isofix seat fittings approved under the Australia standard, as they lock the seat into the car’s inbuilt protection. She’d like forward-facing seats designed for bigger kids, and a performance requirement for harnesses, but she’s happy the latest standard makes a big step forward.

It doesn’t solve all our problems, as New Zealand also accepts seats to US and European standards. But it will help.

Read previous Girl Torque columns here.