The Maryland law states that children must ride in a child restraint system until they are at least eight years old, unless they are over four feet nine inches tall. Most children will reach their eighth birthday well before they reach the height exceptions. All of our surrounding states: DC, WV, NJ, PA, DE, NC and VA also have laws requiring car seat use until 8 years old. The Maryland law states that the child restraint has to be federally approved and used correctly. Booster seats are considered child restraints, as are infant seats, convertible seats and forward-facing seats.