Booster Seats
Booster seats are designed for children who no longer fit in a 5 point harnessed car seat, and who are too small to correctly fit an adult seat belt. The booster helps to correctly position the seat belt over the child's body. Also known as a belt positioning booster, the booster seat correctly positions the vehicle belt over the child so that the belt offers the best protection to the child.
Recent research in New Zealand and Australia shows that children need to use a booster seat until somewhere between 8 and 12 years of age. Age is not the deciding factor however this is move depends on the child's height and mental maturity.
A recent study from Starship Childrens' Hospital (New Zealand) supports international science and specifically showed that for children between 4 and 12 years of age, (Elizabeth Segedin, 2006)
* All 4 and 5 year olds required a car seat or booster seat
* 90% of 6,7, and 8 year olds required booster seats
* 50% of 9 and 10 year olds
* 10% of 11 and 12 year olds still required booster seats
In addition to the above figures, Sam Tormey states the following,
"The rear seat of the average family car is too deep for almost half of adult women to sit upright and comfortably bend their knees over the edge of the seat, and the seatbelt in the rear seat is unsafe for any person less than 145cm tall. Children do not reach this height until around 11 years old, on average. There are two main concerns with being too small for an adult belt: the lap portion rides across the tummy, not the bony hips, causing abdominal injury in a crash, and the sash portion rides across the neck rather than the chest, causing injury to the neck and throat. Long seat cushions exacerbate these concerns by causing the child or small adult to slump so that their knees can bend at the edge of the seat, causing both parts of the seatbelt to ‘ride up’." Sam Tormey is a doctor who writes on medical issues. His practice is in emergency medicine. Sydney's Child August 2008, pg 32.
It is recommended that your child remains in a harnessed restraint right up to 18kgs, then use a full backed booster once they have outgrown their car seat.
Child safety harness and booster seat?
Big kids who need lower seat belt height
Tips for booster safety in cars
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Convertible Booster Seat Convertible booster seats can be used with integral harness for children from 8 - 18kgs, and 14-26kgs with an adult belt or child harness. Some models allow booster use until 36/45kgs. Check your seat or manual for info. It is recommended that children under 12kgs remain rear facing. |
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Full Backed Booster Seat A full backed booster is a dedicated booster that has a back and sides for added protection. The full backed booster can be used with an adult seat belt (lap & sash only) or a child harness (CSH)*. *Plastic booster seats without a versa tether catch cannot be used with CSH. All Polystyrene and half boosters can be. Check your manual for details. |
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Half Booster Seat* Half booster seats are recommended mostly for older children who still need boosting to correctly fit an adult seat belt (lap & sash only). It is not advised to use half booster seats with preschool or small school children. A half booster can be used with an adult seat belt (lap & sash only) or a child harness or a seat belt height adjuster for children over 5 years old. |
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Once your child has outgrown their car seat (around 4 years old/18kgs) the next step is to use a booster seat. There are many booster seats for sale in New Zealand and each fits your car and child differently.
A car seat is outgrown when your child exceeds the maximum weight limit for that seat, or their eyes/ears are level with the top sides of the seat, or the top harness slot is no more than 2.5cm below their shoulder. The image below shows a child who has outgrown their car seat by height.
Before you decide not to use a booster seat for your child it is important to try out the 5 Step Test in each car that your child will regularly travel in. This will tell you if your child is ready to travel without a booster seat or not yet.
The advantage of a booster seat with side wings is that your child is able to sleep within the sides of the seat rather than sitting in a way that could cause serious injuries in the event of an accident. The image below shows 2 young children using half booster seats while asleep.
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Child safety harness & booster seat?
If you find that your child does not sit correctly in their booster seat with the adult seat belt you can use the seat with a child safety harness*. The harness provides 2 points over the shoulders and uses the seat belt as another point across the child's lap, and a small bar keeps the straps together across the child's chest. The image below shows the same booster seat (Safe-n-Sound Pegasus) with adult belt (left) and child safety harness (right).
A child harness can be used with any full back polystyrene booster seat, any half booster seat and any plastic booster seat that has a "versa tether" fitted, this is one that hooks to the car as per normal, and has an extra latch where the child harness can be attached.
There is currently no evidence to state that the harness, or seat belt is better for children of this age, however the harness may provide a more secure fit.
The other option is to lock your seat belt, if your car has restraint belts you can do this by placing your child in the booster seat, buckling the seat belt up and then fully extending the seat belt, once fully released let the seat belt go, a clicking/retracting sound should be heard the seat belt cannot be pulled outwards anymore now, until the buckle is released and fed back into the retractor. If no clicks are heard, your car may not be fitted with restraint belts.
For more information on child safety harnesses click here.
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When a small, undersized child, ( a child who is unable to pass the 5 step test) is placed into an adult belt there are a number of risks that the child is exposed to. Such risks include injuries to the neck, spine and internal organs, as well as injuries caused when the child slides out the lap portion of the seat belt in an accident. The effect of this is known as "sub-marining" and is shown in the image below.
A child will scoot forward in an adult belt simply because they cannot comfortably sit with their back and bottom against the back of the vehicle seat, nor can they sit with their knees comfortably bent over the seat edge.
When a child is uncomfortable, they will find ways to make sure they are comfortable, this means they will pull their lower body forward to rest their knees on the seat edge, leaving a gap behind their back. The child is also likely to place the sash portion of their seat belt behind their neck, since their shoulder is now lower down and the seat belt cuts into their neck causing discomfort.
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Big kids who need lower seat belt height
The Seat Belt Height adjuster is approved for use in cars under the UK ECE standard and has no upper height limit. We do not recommend using this for children who are small enough to use a booster seat. If your child is too big for a booster seat, and passes all steps of the 5 Step Test, but finds the seat belt touches their neck the SBA might be the right system for your child.
Always check that the lap portion of the belt sits low down on the child's pelvis and does not ride up into their stomach. The belt needs to rest flat so the child does not submarine under the belt during an accident.
Shown in the image below is the Auto Safe Products seat belt height adjuster. This can be used with any half booster, or on its own for children who have outgrown their booster seat, this would be between 8 and 12 years of age. It adjusts to various heights as shown below (left).
It can also be used by small adult with seat belts that do not adjust higher and lower.
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Tips for booster safety in cars
!! Ensure that unoccupied booster seats are strapped into the vehicle to prevent them from becoming projectiles during an accident or sudden stop.
!! Do not use the centre belt only for any child, whether in a booster seat or not. When the centre belt needs to be used, use it to secure a toddler/convertible car seat, or for an older child use a child harness also.
!! Always check that your child has enough head support behind then when using a half booster. If not, use a full back booster seat. Your child could suffer from serious head/neck injuries otherwise