New analysis shows methamphetamines - also known as speed or ice - was present in three-quarters of all detections.
Almost one in five drivers caught had multiple illicit drugs in their system.
Victoria Police is regularly deploying highway patrol cars to side streets to catch drug drivers thinking they can outsmart the law.
The effort includes both proactive patrols and intelligence-based tactical deployments.
Victoria Police's entire highway patrol fleet can drug test motorists roadside, with police conducting 150,000 roadside drug tests a year throughout the state.
Last financial year there were 8426 drug driving detections.
Just over 75 per cent of these were for methamphetamines.
This included 17 per cent which showed not only methamphetamines but also cannabis or MDMA.
A small number of drivers - 40 - had all three illicit drugs in their system.
The penalties for getting behind the wheel on drugs are severe.
Even if you’re a first-time offender you’ll be fined $593 and have your licence or learner permit suspended for six months.
Police also have the power to impound your vehicle for drug driving offences.
Police don’t just enforce, they can connect drug users with support services to keep them and other road users safe.
Road policing command Superintendent Justin Goldsmith said drug drivers who think they can outsmart police should think again.
"Every highway patrol car is a drug bus, which means there's nowhere to hide,” he said.
"That includes side streets, where we tactically deploy to catch out motorists actively trying to avoid police.”
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