A magistrate in New South Wales’ Lismore Local Court has dismissed a man’s charge of driving with an illicit drug present, pointing squarely at advice given by the NSW government when it comes to drug driving.

David Heilpern found Robert Collier not guilty on Wednesday, on the basis of an honest and reasonable mistake of fact. Collier reportedly claimed he had driven more than 24 hours after smoking a joint with friends, and argued he had based his decision to drive on information available on the NSW Centre for Road Safety website.

This site, which states cannabis “can typically be detected in saliva by an MDT test stick for up to 12 hours after use,” also says that the length of time illegal drugs can be detected depends on the amount taken and the frequency of use of the drug.

Magistrate Heilpern said it was not controversial that THC, the psychoactive component of cannabis, was “able to remain at detectable levels in the blood for days or weeks, and for months in urine.”

“The 12-hour advice is nothing more than a cruel underestimation that gives people specious information, lulls them into a false sense of security, and leads to greater levels of detection, criminalisation and loss of licence,” he said.

“This case yet again illustrates the absurdity and inaccuracy of that advice.”

“The consequences of this misleading advice, particularly in country areas, can be devastating.”

Magistrate Heilpern is no stranger to reasoning with the state’s tough drug laws. In April, he accepted the passive smoking defence of Nicole Spackman – who had tested positive for cannabis while driving in northern NSW. Spackman argued she had not smoked cannabis but had visited a terminally ill neighbour who had.

The NSW Government, along with NSW Police, has pushed hard to crack down on drink and drug driving in 2019. In May, Minister for Transport and Roads Andrew Constance announced that first-time drink drive offenders would receive an immediate three-month licence suspension and a fine.