Question: what are the requirements to stop using a booster seat?
Answer: In Washington State, the law requires booster seats for children 4 to 6 years old or 40 to 60 pounds. Doctors and safety experts advise that children use booster seats until the seat belt fits correctly. In many cases, this will be when they are at least 4'9” tall, about 80 pounds and about 8 years old.