Honest and Reliable Mistake Defence for Drink Driving Charges

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Being charged with a drinking and driving offence can be a very traumatic and upsetting experience – especially if you thought that you were under the legal limit and were okay to drive. While most people are cautious and will responsibly watch their alcohol intake, there are times when individuals can mistakenly over consume and find that they are legally over the limit to drive responsibly.

Drink Driving – The Basics

The law has categories defining the levels of offence for drink driving. As a Learner, or a Provisional driver the law has a zero tolerance policy for evidence of alcohol in the blood stream.

A learner, P1 or P2 driver is one that is new to operating an automobile and therefore has lesser driving experience than the general population. These are either younger drivers who have recently been licensed, or a person of any age who is new to driving. This category also includes individuals who are not from Australia who are also not fully licensed. These drivers must have zero alcohol in their bloodstream when operating a motor vehicle.

The second category which allows for a small amount of alcohol in the system (0.02 BAC) includes individuals who are in charge of operating the following:

  • Public drivers such as taxi cab drivers, bus drivers, or train conductors
  • Coach or heavy vehicle operators such as tour bus drivers, those operating heavy vehicles over 13.9 tons
  • Dangerous goods vehicles such as those that transport flammable materials etc.

The third category is where the majority of drivers fall; fully licensed drivers and fully licensed drivers from overseas and interstate. These drivers must maintain a 0.05 level of alcohol in their blood or less to be within the legal limit for driving a motor vehicle.

People will sometimes attempt to calculate their own blood alcohol content by counting their drinks, timing their drinks, or choosing to drink alcoholic beverages of a believed lower alcohol content. This can be a very dangerous and inaccurate way to manage their alcohol intake for the purposes of safely operating an automobile. The reason for this is that it is impossible to know for sure the exact alcohol content of any beverage – drinks are almost always poured into different size glasses and the amounts of alcohol used to mix a drink can vary depending upon the person mixing the drink or the liquor used.

In addition, size and body composition can play a very big part in how the body metabolises alcohol. A larger person may tolerate more alcohol before feeling impaired. A smaller person might feel impaired early on. However, regardless of the level of impairment felt, blood alcohol content can still be easily and quickly exceeded.

What To Do If You Are Charged With Drink Driving

In the event that you are caught in these circumstances, you will need to consider a defence for your behaviour. If you have been pulled over by the police, and your breath has been tested within two hours of your arrest by a properly calibrated breathalyzer, and you show that you are above the legal limit for alcohol intake and driving, you will find yourself facing severe fines, possible license suspension and, in the worst case scenario, loss of license and jail time. 

Using the defence of Honest and Reasonable Mistake requires the defendant to have been under the genuine belief that they were not committing a crime. For this defence to be successful, the defendant must show that there was a reasonable and honest belief that they were not in violation of the law. The prosecution must then prove, beyond a reasonable doubt, that the belief was neither honest nor reasonable.

Under the law this the defence of honest and reasonable mistake is considered a mistake of fact. It is possible for the court to determine that the driver truthfully believed that they had consumed alcohol in a quantity sufficient enough to not be intoxicated, and therefore being under the limit to drive.

This could occur in the instance of being out and consuming alcohol, going home and falling asleep, and then waking up to drive elsewhere. At this juncture, it is highly likely that a person could reasonably believe that enough time had elapsed from the previous evening’s events, that they would not still be over the legal limit. However, this defence can only be used in limited circumstances with minimal effectiveness.

Hence, while it is fun to be out with friends socialising and enjoying a few cocktails, it is often best to designate one person to do the driving. For the courtesy of this person remaining sober and taking responsibility for getting everyone home safely, the others can offer to buy the designated driver food and soft drinks. A plan such as this is the safest and smartest way for everyone to have a safe and enjoyable time.


In the event that you find yourself in need of assistance with regard to the drink and driving law and defence, please contact the law offices of Owen Hodge Lawyers. At Owen Hodge, we are always happy to assist clients in understanding the full ramifications of any legal needs. Please feel free to call us at your earliest convenience to schedule a consultation at 1800 770 780.

At Owen Hodge Lawyers, we always strive to provide you with the best legal advice and guidance – no matter your issue. We specialise in a range of law matters, and have a blog that offers in-depth and comprehensive articles. Read our recent posts on how to write a character reference and pill testing pros and cons, all on the Owen Hodge blog today.

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