Belt positioning booster seats can only be used with which type of seat belt?

Belt positioning booster seats are designed to improve the fit of an adult lap and shoulder belt for children who have outgrown forward-facing child safety seats. The booster seat elevates the child so that the seat belt rests properly across the strongest parts of their body – typically, the lap belt should sit low across the hips, and the shoulder belt should cross the middle of the chest and shoulder.

Using an adult lap and shoulder belt ensures that the child is securely restrained in a way that maximizes safety during travel. Since booster seats are intended to position the seat belt correctly, they are not suitable for use with an adult lap belt only or with a child safety seat belt, which is designed for a different type of restraint system. Therefore, the option that specifies the use of adult lap and shoulder belts is the only correct choice for pairing with belt positioning booster seats.