The law reads "Children ages 4 through 5 must be secured by either a federally approved child-restraint seat or a safety belt." If you are stopped in Fla is up to the descretion of the police officer how he reads this. Seatbelts are not made for children under 80 lbs. Every law enforcement officer knows this! If the child is under 40 lbs he/she MUST be in a car seat - be on the safe side, if the child is over 40 lbs and under 60 request a booster seat. This will avoid problems and regardless it will keep your child safer!