DKT- Police can ask a driver to take a breath test at any time.
- Thousands of drivers are tested at random every week.
- A positive result means a second test on another instrument, and that reading is used as evidence.
- Only time lowers your BAC.
How a test works
- You may meet a breath testing station (a booze bus) on the road, or be stopped by police in another vehicle.
- You blow into a small device that gives an indication of any alcohol in your blood.
- If you have not been drinking, there is no problem.
- If the result is positive, you are asked to do a second test on another breath testing instrument. That reading is used as evidence if you are over the legal limit.
- Drivers admitted to hospital after any kind of road crash must give a breath test and, when asked, a blood sample.
- Refusing a breath, blood or saliva test is itself an offence. Read more in drink driving penalties and drug driving.
What changes your BAC
Alcohol affects people differently, and even the same person on different days. The same drinks can give different readings. Factors include:
| Factor | Effect |
|---|---|
| Gender | A woman drinking the same amount as a man of similar size has a higher BAC. |
| Body size | A smaller person has a higher BAC than a larger one. |
| Food | Food slows absorption, so without a substantial meal you reach a higher BAC more quickly. |
| Speed and type of drink | Drinking quickly, or stronger drinks, raises BAC sooner. |
| General health | In poor health the liver processes alcohol less well. |
| Other drugs | Mixing alcohol with drugs raises the risk of a crash even after a small amount of alcohol. |
Only time works
Coffee, exercise, cold showers, fresh air or vomiting will not lower your BAC. They may make you feel more alert, but the liver works at its own pace. The morning after heavy drinking, you are likely still to have alcohol in your blood. Plan how to get home before you start drinking. The safest BAC is zero, even with a full licence. See zero BAC rules.
Based on the Victorian Road to Solo Driving handbook and the VicRoads learner and probationary pages. Rules change from time to time, so check vicroads.vic.gov.au for the latest.
Quick answers
Can police breath test you anywhere in Victoria?
Yes. Police can ask a driver for a breath test at any time, at breath testing stations or after stopping you in another vehicle.
How do you lower your BAC quickly?
You cannot. Only time lowers BAC. Coffee, exercise, cold showers and fresh air do not change the alcohol in your blood.
Can you still be over the limit the morning after drinking?
Yes. After a lot of drinking the night before, you are likely to still have alcohol in your blood the next morning.