Which one is true about child seats in cars?

The statement regarding regular seatbelt use being appropriate for children after age 6, unless they have a slim build, is accurate. Once children hit the age of 6, they typically transition from a child safety seat to using a standard seatbelt, as long as they fit properly. The adjustment to using a seatbelt is based on their size, because a regular seatbelt is designed to fit adults, and a child's smaller frame may require continued use of booster seats until they are tall enough for the seatbelt to fit correctly across their body.

It's important to note that children should be assessed on an individual basis, as their size and development can vary greatly. Proper seatbelt fit involves the lap belt lying snugly across the upper thighs and the shoulder belt crossing the chest, without crossing the neck or face. Hence, if a child has a slim build that doesn’t allow for a proper fit, they may still need to remain in a booster seat until they can securely use the seatbelt. This ensures maximum safety for all children while traveling in vehicles.