When are children under 8 years old required to be in a child safety seat?

Children under 8 years old are required to be in a child safety seat when they are less than 4 feet 9 inches tall. This height requirement is established to ensure that children are secured in a manner that maximizes their safety during a vehicle accident. Child safety seats are designed to provide proper support and protection to younger passengers, as standard seat belts may not fit them appropriately due to their smaller size.

As children grow, their body proportions change, and the use of child safety seats and booster seats is essential until they reach a height where seat belts can adequately protect them. The requirement of 4 feet 9 inches is based on studies that determine when a seat belt fits a child properly, ensuring that both the lap and shoulder belts are positioned correctly for maximum safety.

The other options describe age and height requirements that do not correspond to the established guidelines for child safety seat usage in Texas, making them incorrect. It's important to follow the specific regulations to ensure the best practices for child passenger safety.