Police are urging motorists heading north of Perth to obey overtaking rules throughout the area affected by roadworks.
The stretch of the A9 between Luncarty and the Pass of Birnam is currently the focus of works as part of the dualling programme.
Temporary traffic lights are in place overnight and police say no overtaking rules are in place while the works are ongoing.
However officers have received complaints that the warnings are going unheeded.
A spokesperson said: “Due to a number of complaints regarding overtaking on the A9 between Luncarty and Birnam, we would like to remind drivers that it is an offence to overtake when the signs are displayed.”