Alcohol impairs one's ability to control a vehicle and research suggests that at a blood alcohol concentration (BAC) of 0.05%, the risk of being involved in a traffic crash is double that of a person who has not been drinking at all.
The legal limits
Any alcohol at all will affect your ability to drive. In Australia, it is an offence to drive while your BAC is 0.05 or above.
If you are a novice driver; or have been recently disqualified; or are a holder of an Extraordinary Licence; or are a driver of a taxi; bus; small charter vehicle; vehicle carrying dangerous goods; or a vehicle over 22.5t, the legal limit is zero.
Note: A novice driver is a person that has not held a driver’s licence for a total period of 2 or more years.
Your BAC should remain below 0.05 if you:
- drink no more than two standard drinks in the first hour and one per hour thereafter (for men of average size); or
- drink no more than one standard drink per hour (for women of average size).
However it can vary significantly from person to person.
Alcohol and your health - Australian Alcohol Guidelines - information produced by the National Health and Medical Research Council)