The study, by Neuroscience Research Australia, found that parents are up to five times more likely to choose the correct seat for their child if the size is clearly indicated using shoulder height labels.
"The current system is ripe for error," says Dr Julie Brown of Neuroscience Research Australia. "As a result, parents are moving their children to a bigger seat too early and putting them at risk in the car."
Previous research has found that 40% of children seriously injured in car crashes were sitting in the wrong seat for their size. Many of these injuries could have been prevented by using the right restraint.
"Parents have to wade through complex instructions involving weight, height and age to find the right seat for their child," says Dr Brown. "It's no wonder they sometimes get it wrong."
Dr Brown and her colleagues asked a group of parents to select the correct size child restraint or booster seat using ones marked with shoulder height labels and ones without, which represents the standard seat currently available in Australia.
They found that the clearly visible labels enabled parents to choose the most appropriately sized seat.
"Shoulder height labels make choosing the right seat as simple as choosing the right shoe size," says Dr Brown. "If they're over the line, you move them into the next size and if they're under, you stay in that same seat until next time."
Dr Brown says this research provides strong support for the decision to introduce mandatory shoulder height labels for child restraints and booster seats in Australia. Restraints with these markers should be available in the near future.
She says this concept could also be applied to car seats, with a marking on the seat itself to indicate the minimum shoulder height a child should have before moving from a booster seat to an adult seat belt.
"The power of this measure is in its simplicity," says Dr Brown. "Just a few simple lines could save many lives."
This research was supported by a research grant from the Royal Australian Automobile Club of Victoria (RACV).
The study, "Shoulder height labelling of child restraints to minimise premature graduation", was published in the journal Pediatrics.
