A National Day of Drug Testing, held on Monday as part of Operation Austrans, focused on truck and other heavy-vehicle drivers across the state, and targeted drugs, alcohol, fatigue, and traffic and compliance offences.

Acting superintendent of road policing operations Stuart McGregor said the results from Monday painted an alarming picture of drug culture within the trucking industry.

"None of us want to think that the 12-tonne truck approaching us at 100km/h on the freeway is under control of a person impaired by illicit drugs," Superintendent McGregor said.

"In Victoria, 295 drug-driver screening tests were administered on Monday, with eight heavy-vehicle drivers returning a positive result. Alarmingly that is one in 37 drivers that just should not be driving on our roads."

Nationally, one in every 68 truck drivers tested positive to drug-driving, almost half of Victoria's figure.

Superintendent McGregor said there was a core group of heavy-vehicle drivers putting the Victorian community at risk despite efforts to eradicate drug use among drivers.

The blitz nabbed a B-double driver who was speeding 20km/h over the limit on the Calder Freeway. The driver also failed an oral fluid drug test.

He was found to have been driving with a suspended licence, and was alleged to be using falsified logbooks.

Victorian Transport Association chief executive Peter Anderson said the results demonstrated the need for ongoing co-operation between law enforcement agencies and heavy-vehicle operators.

"As an industry group we attempt to work closely with police and enforcement agencies to educate operators and drivers about the perils of substance abuse," Mr Anderson said.

"Workers in the transport industry are reflective of society as a whole, where an unfortunate minority culture of drug-driving does exist. This certainly does not excuse the behaviour of any heavy-vehicle driver under the influence of drugs, but it is important to frame the matter in its rightful societal context."