Children under eight years old must be secured in an appropriate child safety seat. Child safety seats include infant seats, convertible seats (rear-facing for infants and forward-facing for toddlers), and booster seats that are used with the vehicle lap shoulder belt system.
Children weighing more than 40 pounds may be transported in the back seat of a motor vehicle while wearing only a lap belt if the back seat is not equipped with a lap and shoulder belt system.
Children eight years of age and older but under the age of 16 must be secured in a properly-adjusted safety belt in any position in the vehicle. Persons in violation of this law are subject to a $50 fine for a first offense. Subsequent violations are punishable with a $100 fine.
For more detailed information, view Cyber Drive Illinois