Why do children under age 7 use booster seats?

Children under age 7 use booster seats to ensure their safety during car travel. Booster seats elevate them so that the vehicle's seat belt fits properly across their body, specifically across the chest and lap, reducing the risk of injury in the event of a crash. This age group typically lacks the height and physical development needed for standard seat belts to provide adequate protection. Using booster seats helps prevent serious injuries by promoting proper seat belt positioning.