My son has a high back Car seat in the car, but yet I saw my niece who is about the same height as my son in a booster. What age can they safely go from car seat to booster?
I am not sure if there is a set age. I think it may more be about the preferences of the parent. Another factor would be the height of the child as well.
I agree with BigMac. It's not really about age but height and weight. Some ten year old would fit into a booster seat, others are big enough for a regular seat belt.