Every parent has had the experience of driving a crying child around the block until they fall asleep and kids sleeping in a car seat is a very common sight. It is important that a child doesn't slump out of a shoulder belt or slide down in a car seat when they fall asleep. One of the most important functions of a booster seat is keeping the seat belt in the proper position on the older child. Seat belts need to be positioned low and across the lap and across the shoulder so that if an accident happens, the seat belt will not cause injury to a child's stomach area and even internal organs. It is advised that younger children in booster seats be in boosters with backs. Some booster seats with backs have torso protection that can also help a child from falling sideways when sleeping in a car seat.