Children under the age of 8 must be secured in a car seat or booster seat in the back seat. Booster Seats: Use a belt positioning booster seat when your child's weight or height is above the forward-facing limit for the car seat.The booster seat laws in California require kids to use a booster seat or harnessed car seat if they are below the age of eight. In New York, children should remain in a booster seat until at least age 8. Children in booster seats should remain in the back seat. Children under age 8 must ride in the back seat in either a car seat or a booster seat. Children under eight years of age, weighing under 100 pounds, and shorter than 4'9" need to use a booster chair in the backseat. Eligible participants must attend a one-hour class (available in English or Spanish) and will receive a car seat or booster seat at the end of the class. This is the most up to date and accurate list of state car seat laws. We review each state's car seat law statute every year.