When can I take my child out of a booster seat?

Child safety experts have warned parents about the dangers of taking their children out of a booster seat too early, revealing it can increase the risk of a serious injury in a car accident by 3.5 times.

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Currently, Australia's rules for the safe restraint of children in cars state children seven years of age or older are permitted to move out of a booster seat into a regular car seat with corresponding seatbelt.

It's also recommended to keep them in a booster seat or safety harness if they are under 145cm tall.

However, safety agency Kidsafe Victoria is calling for booster seats to be made mandatory for children until they are 10 years old and/or are able to pass the five-step test.

The five-step test enables parents to check their child is the correct height to occupy an adult seat and includes checking if their knees can comfortably bend over the seat edge, and the sash belt sits across their shoulder rather than their neck or arm.

"Even though our children appear tall in our eyes, most children up to the age of 10–12 will require a booster seat to optimise their safety in the event of a collision," Kidsafe Victoria CEO Melanie Courtney said.

"The evidence shows that it's safest to leave children in booster seats until they have outgrown the size limit. Kidsafe Victoria recommends that children only transition to using an adult seatbelt when they can pass the five-step test. 

“The test is designed to help determine whether a child is big enough to obtain optimal protection from the adult seatbelt. A child can get a good seatbelt fit if the answers to all of the questions in the test are yes.” 

According to Kidsafe Victoria, the risk of serious injury for children who can still fit in a booster seat but don’t use one can be up to 3.5 times higher.

Red Hill mother Lisa Farnsworth is also advocating for clearer guidelines after her 11-year-old son Sam was involved in a severe collision in 2019 that left him quadriplegic.

“I think if not using booster seats was as illegal as not wearing a seatbelt, it might save lives. It might have saved Sam's childhood,” Ms Farnsworth said. 

Dr Warwick Teague, the Director of Trauma at The Royal Children’s Hospital, said the injuries Sam suffered in the accident were a tragic example of what can occur when a child is not the right height for a seatbelt.

“Many people aren't aware of the safety and importance of continuing to use a booster seat until a child outgrows the size limit, particularly when laws allow much younger and smaller-stature children to go without one legally," Dr Teague said.

"Had Sam been supported by a booster seat, it’s likely his injuries would have been less severe."

Australian safe restraint laws state children can use a booster seat from the age of four and up.

Specifically, the rules state children aged 4–7 should be seated in either a forward-facing child seat with in-built harness, or a booster seat with seatbelt or safety harness. Those under the age of four must be in a forward- or rear-facing child seat.

Once they turn seven, children can either stay in a booster seat or move to a regular car seat with a seatbelt, but this is not advised unless the child is 145cm or taller and can pass the five-step test.

According to Kidsafe Victoria, a child can obtain a good seatbelt fit if the answer to all questions in the five-step test are yes. 

1. Back: Can the child sit all the way back against the vehicle seat back? 

2. Knees: Do the child's knees bend comfortably in front of the front edge of the vehicle seat?

3. Lap belt: Is the lap belt sitting low across the hip bones touching the thighs?

4. Sash belt: Does the sash (shoulder) belt sit across the middle of the shoulder, not on the neck or out near the arm? 

5. Stay: Can the child stay seated like this for the whole trip?