Legal Defences for Drink Driving Charges in NSW

25 January 2025 in Criminal Law | 5 min read | skip to FAQs

This article discusses drink driving charges and whether they can be defended or challenged in the court. We present some of the possible defences for drink driving charges.

Driving under the influence of alcohol is sometimes perceived as a trivial offence. However, this assumption is inaccurate. Even for first-time offenders, being charged with drink driving typically leads to a criminal conviction, a monetary fine, and a period of licence disqualification. For those with mid to high-range blood alcohol concentration levels, imprisonment becomes a potential consequence based on the specific circumstances of the offence. Despite a prevalent belief that defending a drink driving charge is futile, the reality is that, while most cases end in a guilty plea, there are instances where a successful defence is possible.

What Is A Drink Driving Charge?

Many individuals commonly use the term “DUI” when referring to drink driving charges, but most charges are, in fact, categorised as PCA (Prescribed Concentration of Alcohol). DUI stands for Driving Under the Influence of alcohol, requiring police to prove that the individual was genuinely “under the influence” of alcohol while driving. This often involves demonstrating visible signs of intoxication, such as bloodshot eyes or erratic driving, which can be subjective and challenging to establish objectively. See the related article on DUI, DUI: Is it the same as drink driving?

On the other hand, PCA, or Prescribed Concentration of Alcohol, allows police to charge someone with drink driving if their blood alcohol level exceeds the prescribed limit, irrespective of whether the person is visibly under the influence of alcohol. This streamlined approach facilitates easier charging, as measuring a person’s PCA can be done scientifically and precisely. Nonetheless, there are potential defence strategies even against PCA charges. We have related articles on high, mid and low range drink driving charges, as well as special and novice range drink driving charges. Please click on the links if you would like to read these articles.

Possible Arguments in Defending a Drink Driving Charge

Challenging The Reading of the PCA

The devices employed by the police to measure your PCA (alcohol meters) are typically accurate and well-maintained, with a presumption of reliability in the readings provided by breath analysis machines. While challenging the accuracy of alcohol meters is generally challenging, there are instances where it might be possible to demonstrate discrepancies between the recorded reading and your actual blood alcohol content at the time of driving. It is crucial to recognise that the offence involves having a prescribed concentration of alcohol in your system while driving. Therefore, the focus is on the reading at the time of driving.

The process usually takes about 30 minutes from arrest to the accurate testing of your PCA at the station (or mobile booze bus). Breath testing devices used at the roadside are prone to errors, and their readings alone are insufficient for charging.

Considering that blood alcohol levels naturally fluctuate over time, the reading recorded by the alcohol meter may not accurately represent your blood alcohol content at the time of driving.

Even though the reading produced by a breath analysis machine at the station is considered accurate, there may be potential challenges to that reading. In cases where your PCA is in question, your lawyer might engage an expert, such as a pharmacologist, to calculate your likely reading at the time of driving. This calculation involves various factors like the number of drinks, alcohol content, consumption timeframe, food intake, physical characteristics, and any medical issues or medication.

In essence, it may be possible to demonstrate that, while you were over the limit during the breath analysis, you were not over the limit at the time of driving, resulting in a defence against a PCA offence. Moreover, even if over the limit, these principles could potentially be applied to reduce the range of the offence, leading to a significant reduction in applicable penalties. The success of such a defence depends on various factors, and consulting an experienced criminal lawyer is essential.

Honest and Reasonable Mistake Defence to PCA Charges

The law provides several defences to drink driving charges, one being the “honest and reasonable mistake of fact” defence, established in the Proudman and Dayman case. This defence asserts that you are not guilty of a drink driving offence if, at the time of driving:

1. You honestly believed you were under the limit.
2. The court deems it reasonable for you to hold that belief based on your circumstances.

Application of the Defence

This defence can be challenging to succeed on, as courts are cautious about letting drink drivers evade charges based solely on a claim of not knowing they were over the limit. While each case is unique, here are some scenarios where this defence might be considered.

Morning After the Night Before as a Defence to PCA Charges

If you had been drinking the night before, had sufficient sleep, and genuinely believed the alcohol would have cleared from your system the next morning, the court might find it reasonable.

Relying on Rule of Thumb

If you followed the outdated rule of thumb taught by Roads and Maritime Services (now Transport for NSW) for learner drivers, the court might consider an honest and reasonable mistake of fact defence.

Drink Spiking

If you suspect your reading is elevated due to drink spiking, this defence can be applicable. These examples don’t cover all potential scenarios. Consulting with an expert criminal lawyer is crucial to determine the viability of this or other defences based on your case’s specifics.

Two-Hour Rule

It’s lesser-known issue that police cannot rely on a breath test taken over two hours after you last drove. This means if the test exceeds this timeframe, the reading might not be admissible as evidence of intoxication.

Home Safe Rule

Equally obscure is the “home safe” rule, stating that police cannot force a breath test at your home. If the police breach this rule, the evidence of your reading may be inadmissible in court. The legal interpretation of what constitutes a person’s home can be complex.

How can BSM Sydney Lawyers assist you?

It is important that you receive legal advice. Drink driving offences are criminal offences which may result in a criminal record and possibly a jail sentence. The criminal lawyers at Brander Smith McKnight Sydney Lawyer have assisted many hundreds of clients with these charges. Our criminal lawyers will provide you with legal advice to ensure that you achieve the best possible outcome. This may include:

1. Preparing you for court
2. Obtaining character references
3. Obtain evidence of hardship of licence disqualification, such as caring for a sick relative or the need for a licence for employment
4. Obtaining medical or psychological reports
5. Obtaining references from employers
6. Completing traffic offender programs

BSM criminal lawyers will listen to you carefully, evaluate your situation and the likelihood of a successful outcome. Our Sydney lawyers will appear in court for you and strongly argue your case. We will achieve the best possible outcome for you. Our senior criminal lawyers offer a free 20-minute consultation to assess your individual case.

FAQs

BSM Lawyer Sydney have offices conveniently located in Sydney CBD, Sutherland, Parramatta, Shellharbour and Wollongong.