California vs New York

California and New York are both strict states, and on the two rules that affect the most children they are an exact match. Both require a child under 2 to ride rear-facing. Both keep a child in a car seat or booster until age 8 or 4 feet 9 inches (about 57 inches). So for the everyday questions, when does my toddler turn forward and when does my child stop using a booster, the two states give the same answer. The differences are at the edges: the back seat, the size of the fine, and a California change coming in 2027.

California requires children under 8 to ride in the back seat where one is available; New York recommends the back seat for children under 13 but does not require it by law. California's fines also run higher: a base of about $100 for a first offense and $250 for later ones, plus county penalty assessments, versus New York's civil fine of $25 to $100 for a violation involving a child under 8. New York also lets a first-time offender avoid the fine by buying an appropriate restraint before the court date. So California carries both the back-seat mandate and the heavier financial penalty.

California is about to extend its lead. Starting January 1, 2027, Assembly Bill 435 redefines what counts as being properly restrained by a seat belt. The belt must pass a five-step fit test, and a child who cannot pass keeps using a booster even after reaching 8 years or 4 feet 9 inches. New York has no comparable rule and still graduates a child purely by age or height. So while the two states are even on booster age today, California will tie graduation to actual fit in 2027, which can keep some children in a booster longer than New York's rule would.

The law that applies is the law of the state you are driving in. Because the core ages match, a family moving between New York and California rarely has to change car seats based on the move itself. The two practical differences to watch are California's back-seat requirement under 8 and, from 2027, its seat belt fit test. If you default to California's tougher rule, keeping a child under 8 in the back seat and in a booster until the belt truly fits, you will satisfy what either state asks of you.