When using seatbelts too big for their size, children can suffer severe head, spinal and abdominal injuries in a crash.
So why did the Government choose to ignore this when amending the law? Cost.
The Ministry of Transport says the price of a booster seat could be significant for low-income families. It estimates that, based on an 80 per cent compliance rate, if children were to stay in a booster seat until they were the height recommended by Safekids it would cost $19.6 million compared with $13.8 million.
Okay, yes, it will cost more but is that a reason for the ministry to ignore international research? Can we turn a blind eye to research that shows the risks of serious injury for children using seatbelts too big for their size?
Clearly, the Government feared a backlash of extending the new restrictions any further.
We should consider too that the same Government has already indicated that funding will be forthcoming for the next America's Cup Challenge, after spending $36 million on this year's unsuccessful campaign.
If cost is an issue then couldn't the Government redirect some of this money into a subsidy for car seats for low income families so they can afford to buy the regulation seats?
The Government's argument that extending the rules would have cost too much would be dismissed by Te Puke mother Monique Lints.
It is nearly 20 months since her family were involved in a horrific head-on crash that robbed her son Aiden of the ability to walk unaided.
Details of the crash, and Aiden's progress since, have been reported widely, but what has never been revealed is that Aiden, now 4, was not in an appropriate car seat at the time of the crash.
Aiden, pictured below, was placed in the middle, in a half booster seat, secured by a lap belt.
When their four-wheel-drive and a van collided head-on, Aiden's leg was broken and spinal cord badly damaged, with the prognosis that he would be in a wheelchair for the rest of his life.
Lints says it's possible he would still be walking today if he had been in a car seat appropriate for his size and age.
She hopes to encourage others to secure their children properly.
"Children are the most precious things in the world," she says.
The Government would be wise to take note.