Recent changes to South Australia’s drink-driving laws have resulted in a situation in which a person can be convicted of drink-driving, even if they were stone-cold sober at the time they were in the car.

Imagine this scenario. It’s Friday afternoon and you’re driving home from work, looking forward to enjoying a relaxing beer or wine with your partner.  On the way, another motorist flies past you and gives you ‘the bird’, but you have no idea what he’s on about, and frankly, you don’t care.  You get home, put up your feet and enjoy three or four glasses over the next hour knowing that you have no intention of doing anything but sitting in front of the TV that evening. The next minute there’s a knock at the door and the police are there!  They say that the other driver alleges you cut them off.  Then, incredibly, they want to conduct a breath test to see if you were over the limit.  You tell them you didn’t have anything to drink before getting into the car and that the only alcohol you’ve consumed was at home.  Nevertheless, they tell you that you were driving in the last preceding three hours and require you to submit to a Breath Analysis. Unsurprisingly, the result is that you’re over the legal limit, but that shouldn’t matter because you weren’t at the time you were driving. Think again. You will be convicted of drink-driving and lose your licence with no means to defend the charge. How has this come about?

What’s the law?

Until recently, the law in South Australia was that if you consumed alcohol after you had been driving, then you were able to lead evidence as to how the alcohol you consumed in the intervening period might have affected your Breath Analysis result. This defence of ‘intervening drinking’, was obviously not common because, in the vast majority of cases, motorists are stopped while they are driving and immediately tested so there can’t be any suggestion that they had something to drink after the event.

The onus was always on the person charged to lead expert evidence as to how this intervening drinking would have affected the reading, and there was no duty on the police to do anything about it since they could rely on the result of the Breath Analysis, along with a legal presumption that the result of that Breath Analysis can be relied on as proof of the person’s blood alcohol concentration for the preceding two hours.  The Supreme Court of South Australia has long ago called this ‘Draconian’ legislation since obviously a person’s blood alcohol concentration doesn’t stay the same.  However, because of the virtual impossibility of police being able to prove the actual BA concentration at a particular time, the law says that if the police follow all the requirements and procedures relating to Breath Analysis tests, then the result is deemed to have been the person’s blood alcohol concentration for the two hours prior.  Even then, if you had only just had your last drink you could have been under the limit when you were stopped by police, but over the limit by the time you submit to the Breath Analysis, and so long as that was done within two hours of driving the result could be used as proof you were over.

What’s changed?

All this changed in recent amendments to the Road Traffic Act which came about in December 2022.  To start with, the ‘legal fiction’ that the result of a person’s Breath Analysis Test is deemed to have been their blood alcohol concentration for the past two hours has been extended to a period of three hours.  Parliament apparently made this change so as not to inconvenience the police and to take the pressure off of them from having to perform a Breath Test within two hours of driving.

More significantly, the very important provision that allowed a person to lead evidence as to the fact of any ‘intervening drinking’ was effectively removed by Parliament as a result of these changes. Apparently it was suggested that this would, “Assist in the prosecution of repeat offenders who use the defences as a ‘loop-hole’ to avoid prosecution.”  Such a ‘loop-hole’ can’t be used by someone who is stopped by police while they are driving and which accounts for most of all drink driving charges.  It could be said that there is simply no logic to that argument.

In addition, the rationale seems to have been that by removing the ability of a legitimate, genuine defence to be presented to the Court it would relieve resources on Forensic Science, who would be required to conduct those calculations, however as stated earlier, the onus was always on the defendant to come up with that evidence.  If they didn’t, then the police could still rely on the result of the Breath Analysis test.

The end result is that there is absolutely no way to defend a drink-driving charge on the basis that you had been drinking after you were driving if police conduct a Breath Analysis within three hours of the time of driving, even if you were as ‘sober as a Judge’ at the time and had only consumed alcohol after your journey had ended.

There can be no suggestion that drink-driving should be condoned, or that actual offenders should not be deterred from re-offending.  Nevertheless, to have created the situation that removes any opportunity to lead evidence of the fact that you had no alcohol in your blood at the time you were driving might be regarded by some as a serious encroachment on civil rights.

When you add to this the fact that the police can, upon obtaining a positive result, immediately disqualify your licence before the case has even gone to Court, then motorists are really left with no alternative but to resign themselves to the fact that no alcohol should be consumed whatsoever less than three hours after the last time you were behind the wheel.

You just never know.

As stated, the only way to defend a charge of drink-driving is to review whether all of the legal requirements relating to the conduct of the Breath Analysis were complied with. This is a highly technical area of law and Websters Lawyers have specialist traffic lawyers who can advise you to know where you stand legally if you are charged with drink driving or any other type of traffic offence.