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Our child is ready to switch from a five-point harness child car seat to a car booster seat, and we looked at a couple of models in a store. We saw one model that has clips on it to clip into the anchors that the five-point harness uses.

Is there any point to this? The difference is that a five-point harness replaces the regular seat belts and must be strongly connected to the car's frame. A booster seat just holds the seat belt in a safe position on the child's body. I don't think there's any tension between the car and the booster seat in a crash, so why would it need to be anchored?

Has anyone seen any reliable information on this feature?

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Actually, it sounds pretty handy to me, ours is always shifting when my daughter gets in and out of the car and so it doesn't remain in the best position to line up the belt the way it should. I have to keep a close eye on her getting in and out so the seat is in the right position even though she is otherwise old enough to handle the whole routine, belt herself etc. –  balanced mama Nov 19 '12 at 1:40

1 Answer 1

Imagine what happens in a frontal crash - an unanchored object will continue forwards at the speed it was travelling (say 70mph if we are talking about a UK motorway).

So with the seatbelt holding the child, if the car came to an instant halt, the booster would effectively hit the child at 70mph in the back of the knees. (Yes I know this is a huge simplification, but it shows the principle)

With the booster anchored as well, it will decelerate at the same rate as the child, so this impact will not occur.

Boosters are pretty light, but as kinetic energy is 1/2 x Mass x (Velocity squared) anything you can do to reduce that v-squared really helps.

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I guess it depends on the booster, but the ones our kids had, the seatbelt when under the arm-rests of the booster so the belt anchored both the child and the seat. –  DA01 Oct 22 '12 at 16:00

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