Final answer:
The age at which a child must be positioned in the rear seat is dependent on local laws but generally follows child development stages, starting with a rear-facing car seat, then moving to forward-facing and booster seats as they grow.
Step-by-step explanation:
The safety of children in vehicles is regulated to decrease the risk of injury during transportation. For the youngest age group, children ages 0 to 2.5, it is recommended that they be placed in a rear-facing car seat in the back. As children grow, the position and the type of car seat will change, always aiming to maximize their safety. Once they outgrow rear-facing seats, typically around age 2.5, they can move to a forward-facing seat with a harness, which is usually appropriate for children ages 2.5 to 6. Beyond this, children should be in a booster seat until they are tall enough to properly fit an adult seat belt, normally when they are between 6-13 years old. It is around the age of 13, depending on their size and local laws, when children can start sitting in the front seat.
It is crucial to adhere to the specific laws of your locale, as they can vary widely. These laws take various factors into consideration, such as the child's age, height, weight, and developmental stage, to ensure the child's maximum safety in vehicles.