Car seats first became mandatory in the state of Tennessee in 1978. Since then, all 50 states, the District of Columbia and the U.S. territories of Guam, the Virgin Islands and the Northern Mariana Islands have all passed laws requiring car safety seats for infants and small children.
In addition to basic safety seat laws, 48 states, the District of Columbia and Puerto Rico have laws that require children who are not large enough to use adult seat belts to have booster seats or similar devices. The only states that do not require these are South Dakota and Florida. In addition, Florida, Louisiana, New Jersey, New York and California require seat belts on school buses.
Specific details of child safety seat laws vary from state to state. Some laws specify that infants use rear-facing seats, and these are recommended for all infants up to 12 months old. Forward-facing seats with harness straps are then recommended until the child reaches the maximum height and weight limit suggested by the manufacturer. States have various height limits before a child can advance to an adult seat belt, but the average is about 4 feet 9 inches. Most state laws also recommend or require that children 12 years and under sit in the back seat.