SSHHH. Keep still and be very, very quiet - you're aboard a school bus.
In a bid to curb unruly, noisy school children, Duffy's City Buses has begun a silent safety policy aboard two of its school buses.
School children are expected to sit still and be quiet.
The policy, which has the support of the state Education Department, started prior to the end of the last school term.
According to Duffy's City Buses owner Chris Duffy, the measures were there to protect school children and bus drivers.
"Unfortunately, there is no middle ground between silence and extremely excessive noise on a couple of school runs," he said.
"Extreme noise affects a driver's ability to concentrate effectively.
"Consequently, as safety-conscious bus operators, we have been compelled to put these safety protection measures in place."
The number 72 Bargara school bus observes the silence policy with the full support of Bargara State School, according to a Facebook post.
An Education Department spokeswoman said student safety was its highest priority.
"The department does not condone any behaviour or activity that puts another student or member of the public at risk," she said.
"Duffy's bus company, in consultation with local principals, have instituted the 'silent safety rule' for before and after-school routes in response to concerns around the level of noise on the buses as students go home for the day."
What happens if a child breaks the rule?
"Warning letters are issued to students who continue to talk loudly on the bus or act in a discourteous manner towards other passengers or the driver," they said.
Update your news preferences and get the latest news delivered to your inbox.