Final answer:
In Oklahoma, children under what age must be in a child passenger restraint system? Children under the age of 2.5 must be in a child passenger restraint system in Oklahoma.
Step-by-step explanation:
In Oklahoma, children under the age of 2.5 must be in a child passenger restraint system, which typically includes a rear-facing car seat. Children ages 2.5 to 6 must use a forward-facing car seat, while children ages 6 to 13 must use a booster seat. Once children reach the age of 13, they can use a seat belt. These mandatory safety requirements aim to protect children and reduce the risk of injuries in car accidents.