Are children required to be in a car seat, and if so, until what age?

Children are required to be in a car seat or booster seat until they reach at least 9 years old or 145 cm (4'9") tall. This requirement is based on safety standards that aim to ensure that children are properly restrained in a vehicle to protect them in the event of a crash.

The reasoning behind this regulation is that standard seat belts are designed for adult-sized occupants, and very young or small children may not be adequately protected by them. Using an appropriate car seat or booster seat ensures that the child's body is held securely and that the seat belt fits them correctly. This significantly reduces the risk of serious injury or death in crashes, highlighting the importance of appropriate restraints for children as they grow.

The other choices do not accurately reflect the guidelines designed to keep children safe while traveling in vehicles. Car seats are not optional for all ages, and simply being under 40 pounds or sitting in the front seat does not determine when a child can transition out of a car seat. There's an emphasis on specific age and height requirements for the child's safety rather than just weight limits or seating location.