THE signage to slow Pialba-Burrum Heads Rd near Petersen Rd to 80kmh was put up on Tuesday.
The decision to change the notorious stretch from 100kmh to 80kmh was made after a six-year-old boy was seriously injured in a crash last week.
The boy remains in a serious but stable condition in Lady Cilento Hospital in Brisbane.
The previous 1.5km stretch of 80kmh speed zone has been extended to 5kms, now taking in a number of black-spot intersections.
Residents had for years campaigned to have the stretch of road slowed down after a number of crashes along the stretch.
Minister for Main Roads Mark Bailey and Member for Bruce Saunders last week made the announcement the speed limit would be changed.
Petersen Rd resident Janina Barnes welcomed the news of the signs being erected.
"I just hope that now that it has dropped that there are less accidents," she said.
The state government is also conducting a full safety audit along Pialba-Burrum Heads Rd.