Contrary to popular belief, there are actually two charges relating to drink driving; driving under the influence of alcohol (DUI) and driving with a prescribed concentration alcohol (PCA). The main difference between the two offences is that for a PCA charge, evidence from a Breathalyzer or a blood sample is required to support the charge. Your physical state and mannerism are irrelevant to a PCA charge. For a DUI charge, your mannerism and behaviour are directly relevant as they form the basis of the assessment that you were driving under the influence of alcohol. This article considers driving under the influence of alcohol, as driving under the influence of drugs has its own evidentiary requirements.
The DUI offence
Victorian law provides that anyone who operates a motor vehicle whilst under the influence of alcohol which impairs proper control over the vehicle is guilty of an offence. Whilst the offence sounds quite subjective, there are several elements that the Police must prove, namely that you:
- Operated a motor vehicle;
- Whilst under the influence of an intoxicating liquor; and
- Which made you incapable of having proper control of the vehicle.
Evidence gathered by the Police officer will include observations about your mannerisms and physical appearance, such as bloodshot eyes, slurred speech, a perceived smell of alcohol on the breath, disorientation or poor coordination. This assessment will form the evidence for the offence and does not require additional proof, such as a reading from a blood test or Breathalyzer.
Penalties for driving under the influence of alcohol
If you are found guilty, the penalties that you can face will depend on whether it is a first-time or subsequent offence. For a first-time DUI offence, you can face a fine and up to a maximum of 3 month imprisonment, plus 2 years licence disqualification. For a second offence, you can face a fine and up to 12 months imprisonment with a 4 year licence disqualification period. For any subsequent offences, the maximum penalty is a fine plus up to 18 months imprisonment and a 4 year licence disqualification period.
Are there any defences?
As proof of the DUI offence relies only on the assessment of the Police Officer who made an observation of your physical state, the assessment can be challenged, especially if no other evidence (such as a Breathalyzer reading) was taken at the time. It could also be relevant to your case if you have prescribed medication and were taking it at the time of the alleged offence, as this would give an explanation as to your observed condition, suggesting that you were not under the influence of alcohol at the time.
You can also challenge the fact that you did not operate a vehicle whilst intoxicated and therefore were not in charge of the vehicle. For example, if you were merely asleep in the vehicle, which was parked at the time. However, the nature of your defence available to you will vary and depend on the circumstances of your case.
 Road Safety Act 1986 (Vic) s 49(1)(a).
 Road Safety Act 1986 (Vic) s 49(2)(a).
 Road Safety Act 1986 (Vic) s 49(2)(b).
 Road Safety Act 1986 (Vic) s 49(2)(c).
 Road Safety Act 1986 (Vic) s 3AA.
 Halley v Kershaw  VSC 439.