Wear a helmet – it’s the law!
As of 1 February 2017 it became “a requirement for quad bike riders and the drivers of utility off-road vehicles, and any passengers carried, to wear an approved motorcycle helmet when the vehicle is operating on a road or road-related area.
“Children under the age of 8 are prohibited from being carried as passengers on quad bikes and utility off-road vehicles, as well as any child of any age if they are unable to sit with their feet at on the floor and hands on handholds.”
This information is taken directly from the https://www.qld.gov.au/transport/registration/register/conditional/ about-conditional/index.html#helmet