Mist has taken over the cooler mornings in the wheatbelt and will only become more prominent when it gets colder.
Snr Sgt Geoff Dickson said fog is a reality at this time of the year, in the Avon Valley.
He said the best way to be safe on the roads is to be visible.
“Driving with your headlights on is perfectly legal,” he said.
“With fog, you should have your headlights on low beam.
“Fog Lights are okay in foggy conditions, but you must turn it off when it is gone.
“The law is very clear on that.”