Atkinson is an English-language surname. The name is derived from a patronymic form of the Middle English Atkin.
These are much more conservative than state laws, in general (for instance, everyone should be in a booster seat from about age 4 to at least age 8) but remain less conservative than some of the european standards (for instance, the European Child Safety Alliance recommends that children remain in rear-facing carseats until 3 years of age).
Even at age 4, most children are NOT ready to use a booster seat. A booster seat just sits on top of the car's seat and the adult seat belt is used to buckle in the child. At this age, most children fidget/ lean out of the belt to tease a sibling or to pick up a toy.