A squad of covert police motorcycles launched ahead of the Christmas period has already nabbed dozens of drivers using mobile phones or flouting seatbelt laws.
It is understood police started using a permanent fleet of unmarked motorcycles this week.
In just three days, officers on those motorbikes issued more than 120 infringements for drivers using mobile phones or not wearing seatbelts and issued another 34 infringements for other traffic offences.
A fleet of unmarked motorcycles leased from a variety of motorbike companies was used during trials last Christmas period and at Easter this year.
Police laid more than 1520 charges for mobile phone use during those operations.
Officers wearing plain clothes and fluoro vests had cameras attached to their helmets to record offending behaviour to use as evidence.
The success of those trials targeting errant drivers led WA Police to buy several unmarked motorcycles for a permanent covert fleet.
Analysis of crashes since January shows inattention was the single biggest cause of serious and fatal crashes and the covert fleet proved successful for nabbing drivers using mobile phones or not wearing seatbelts.
While distraction and inattention are difficult for officers to monitor, mobile phone use is an obvious law-breaking behaviour that police can easily enforce.
During the trials a marked police motorbike or car was needed to work with the undercover officer to pull over drivers. But officers on the new motorcycles can work alone because the bikes are fitted with their own communications equipment and emergency lights and sirens.
The Christmas-New Year double demerit period begins on Friday and ends on Sunday, January 4.