Every state makes their own laws regarding child safety seats. All states have some form of law about the safety of children in cars, as detailed on the Insurance Institute for Highway Safety website.
All children must be properly fastened in a safety seat no matter what state the driver is in. The height and weight limit for car seats, booster seats and riding in the front seat varies by state. It is best to contact the local authorities to find out the laws in that area.
All states except for New Hampshire have seat belt laws for adults and children, as stated on the Insurance Institute for Highway Safety website. Some states allow the police to stop a vehicle for the sole purpose of giving a citation for not following the safety belt laws. The police must have another reason for pulling a vehicle over in other states.