To revise child car seat regulations so they are based on height and weight, not just age. Children under age 2 who weigh 30 pounds or less would have to be in a rear-facing child seat, and children age 2 through 4, or who weigh between 30 and 50 pounds, would have to be in a rear-facing seat or a forward-facing child seat with harness. Children between age 5 through 11 who weigh between 30 and 50 pounds and are less than 57 inches tall would have to be in a booster seat.   Official Text and Analysis.