Seat belts are not designed for children. Young children are too small for seat belts and too large for toddler seats. A booster seat raises your child up so that the seat belt fits right—and can better protect your child. The sholder belt should cross the child's chest and rest snugly on the shoulder, and the lap belt should rest low across the pelvis or hip area—never across the stomach area. Your child's ears shouldn't be higher than the vehicle's seat back cushion or the back of a high-back booster seat.