Which car seat/booster to use?

[Jellyboobs]

My daughter is 8 next week, and is 125cm tall, 28kg. I am very confused about what kind of car seat she should be using now. She would like to have a plain booster cushion but some sites say they're not allowed/not safe. Is there somewhere I can check using her height, age and weight to give me a proper answer?

What's she using at the moment? She would be legal on a plain booster cushion, yes, but this won't offer as much protection from an accident as a high backed booster seat will. Ideally you want to keep using the high backed booster for as long as she can physically fit into it. For example most high backed booster seats have shock absorbing materials in the headrest to help cushion her and protect her neck in the event of someone hitting you from the side. They also tend to have an adjuster for the shoulder belt so that it will fit her shoulder correctly and helps keep it in place if you were in a frontal crash or rear shunt. Without this she might move around a lot more in a crash or even bend right over the seatbelt which can be a cause of internal injuries.

There is no calculator as such, as it depends on much more than simple factors like height and weight (build, leg length, seatbelt placement in the car, maturity) but 125cm is the minimum height for the backless boosters on the market now. If you are considering moving her, I'd check how she fits onto the booster cushion. Some children are tempted to push it forwards and sit in the crease behind it which would really badly affect the seatbelt fit. Even if she sits on it properly, look at where the shoulder belt is on her. It should cross her collarbone to be safe. If it's higher it won't distribute the crash forces correctly in a crash and might irritate her neck which could tempt her to put it under her arm which is very, very dangerous if you crashed (high risk of punctured lung).

If you decide to move her to a booster cushion it might be an idea to keep her high backed booster around in case you do any long drives where she might fall asleep. That's the one thing DS1 misses about his - when we do night time driving and he wants to nap he finds it really uncomfortable without the headrest.

You might want to have a watch of this comparison crash test - and bear in mind that's the 10yo crash test dummy, a 7yo would be even smaller on the backless one and less protected by the seatbelt.

Yes, it's perfectly legal to use a booster cushion for your daughter but it obviously won't offer the same protection as a high back booster.

Pic of the current legal requirements.

@BertieBotts that is fantastic, thank you.
She’s currently in a britax car seat that has grown with her, extendable back support etc. She has been asking for a booster cushion (no back) as some of her friends have them. I had originally thought they had been banned for safety reasons, but I can see now that they rules have just changed.
The crash test is quite shocking, I will definitely keep her in at least a high back booster, thank you!

@Shmithecat2 thank you very much, that’s really clear, I appreciate your reply!