do 5 year olds need car seats

Yes — in Australia, a 5-year-old must use an approved child restraint: either a forward-facing seat with an inbuilt harness or a booster used with a properly fastened seatbelt (AS/NZS 1754).

Back seat, please; the front is only allowed if there’s no back seat, or all rear spots are already occupied by children under 7.

Make sure the belt sits low on the hips and across the chest, not the neck — if it looks like a pirate’s sash, it’s wrong.

States add tiny flourishes, but the rule of thumb holds: ages 4 to under 7 = booster/restraint, and after that only if the adult belt fits properly.

If in doubt, get the restraint professionally fitted; it’s cheaper than explaining physics to a windscreen.