SMILE for the camera when it's switched on at the corner of Great Western Highway and Carlisle Avenue next month.
Roads and Maritime Services officers have spent the last month installing the red-light speed camera at the busy Mount Druitt intersection.
An RMS spokeswoman said it will be ona trial from October before infringements are issued.
"The state government prioritises the cameras based on the frequency and severity of crashes and road-safety risk," she said.
"There are four cameras in the St Marys and Mount Druitt area which aim to increase safety for all road-users.
"Extra cameras will be considered in line with the NSW Government's strategy and commitment to road safety."
St Marys has cameras on the corner of Great Western Highway and Charles Hackett Drive and at Mamre Road and Saddington Street.
Carlisle Avenue, Great Western Highway and Palmyra Avenue are among 500 sites across NSW destined for mobile speed cameras.
Reaction on the Star's Facebook page was mixed.
Todd Sachs wrote: "They need them on the M4 near the M7. There are too many accidents there."
Michael McHugh wrote: "If you get caught it's because you were in the wrong. It's a voluntary tax — don't want to pay it, don't break the law. Simple."
Others believe the cameras are there to make revenue and called for more police on the roads.
Paula Smith Edmonds wrote: "The only thing a speed camera does is slow people down until they pass it. It won't fix the problem. Maybe it will just get some of the government's excessive spending back."