Illinois vs Indiana

The Illinois-Indiana border runs right through the Chicago metro, so this is a daily-commute comparison for a lot of families. Illinois is the stricter state. It requires a child under 2 to ride rear-facing unless they weigh 40 pounds or are 40 inches tall, and it keeps a child in a car seat or booster until age 8. Indiana sets no statutory rear-facing age; it requires a child under 8 to be in a child restraint system used according to the manufacturer's instructions. Both states release a child to a seat belt at age 8, so the booster finish line matches, but the rules for the youngest children do not.

Illinois requires a child under 2 to ride rear-facing unless they have already reached 40 pounds or 40 inches. Indiana law does not name a rear-facing age and leaves the seat type to the manufacturer's instructions for the child's size. So a parent who turns a 15-month-old forward is breaking the law in Illinois but not in Indiana. Pediatricians recommend rear-facing as long as the seat allows in both states, so Illinois simply makes the best practice a citable rule for the under-2 group.

On boosters the two states line up. Both require a child to stay in a child restraint or booster until age 8, and both then allow a seat belt. Neither state writes a separate 4 feet 9 inch height-out into the rule, so the age-8 mark is the practical finish line in both. Neither state requires children to ride in the back seat, though both recommend it for children under 13.

Illinois sets a fine of $75 for a first offense and $200 for a later one. Indiana handles its penalty through the citation schedule rather than a single fixed figure in the restraint statute. The law that applies is always the law of the state you are driving in, so a parent commuting between the two should default to Illinois's stricter rule: keep any child under 2 rear-facing. Do that and you satisfy Illinois while sitting comfortably inside what Indiana asks, and the booster rule is identical wherever you cross the line.