At what height does a child need to be secured in a safety seat while being transported in a motor vehicle?

The correct answer is based on guidelines for child safety in vehicles, which specify that children should be secured in a safety seat until they reach a height of 4 feet 9 inches. This height is recognized as the point at which a child can transition from a booster seat to a standard seat belt safely.

A child who is shorter than this height may not be adequately protected by a seat belt alone, as the belt may not fit properly, risking injury in the event of a crash. The use of safety seats and booster seats is crucial in ensuring that the seat belt positions correctly across the child's lap and shoulder, providing maximum protection.

Additionally, the guidelines promoting this height are based on safety research that identifies optimal conditions for restraining children based on their physical development rather than just age. This makes the specified height a critical benchmark for ensuring children are properly secured in vehicles to enhance their safety.