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Drug Driving and Mistake of Fact in QLD


It is an offence against section 79(2AA) of the Transport Operations (Road Use Management) Act 1995 to drive a motor vehicle with a relevant drug present in one’s blood or saliva. This offence, colloquially called ‘drug driving’, is complete where a person is in control of a motor vehicle with even trace amounts of prescribed substances in their system. The Police are not obliged to prove any particular concentration of the drug in a person’s blood or saliva, merely its presence in discernible amounts.

Given that all drugs are metabolised differently in the human body, and every human body is unique in respect of its ability to metabolise particular drugs, it is impossible for anyone to accurately predict whether or not traces of a drug will be present in their system after they have used. While there does not appear to be a particular consensus in the scientific literature (mostly because there is scant scientific literature on the topic), it seems clear that many common drugs like cannabis and methamphetamine can linger in trace amounts in a person’s bloodstream for days, and even weeks, after they have been ingested.

In New South Wales a person recently faced trial for drug driving with cannabis in his system 9 days after he had last used the substance. A Magistrate determined this person was innocent of the offence because he held an honest, and reasonable, view that there would be no traces of the drug in his system after 9 days and so drove his motor vehicle.

Could this reasoning be applied in Queensland? The short answer is, no.

Queensland law does make provision for a defence called ‘mistake of fact’, which says that a person who does an act while under an honest and reasonable, but mistaken, belief as to ‘any state of things’ is not criminally responsible for the act to any greater extent than had the ‘state of things’ been true. This defence, however, is expressly excluded in relation to drug driving offences (and drink driving offences for that matter).

Subsection 79(12) of the Transport Operations (Road Use Management Act) 1995 provides that a defence of ‘mistake of fact’ does not apply to any offence committed against section 79 and, therefore that defence does not apply to an offence of drug driving (or any drink driving offences, which are also contained within section 79).

If you have been charged with drug driving you should contact one of Armstrong Legal’s lawyers as soon as possible to discuss your case. Contesting your matter on the basis of a mistake of fact (as was done successfully in New South Wales) will not succeed in Queensland and might expose you to a more severe penalty than would otherwise be deserved.

Image Credit – Federicofoto © 123RF.com

Written by John Sutton on December 5, 2016

John is partner of Armstrong Legal and head of the Criminal Law Division. The experience John possesses, being a high quality mix of defence and prosecution skills, together with his team at Armstrong Legal, mean you can be certain of accurate, dependable and practical advice on how your matter can dealt with. View John's profile


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