We all know that alcohol and vehicles are not a good mix, but how does alcohol affect your driving and what do you need to be aware of as a motorist?
Despite a reduction in the number of crashes involving alcohol in recent years, 1 in 4 driver and rider fatalities still have a blood alcohol concentration above the legal limit.
Even the smallest amount of alcohol can affect your driving ability and increase your chances of being involved in a crash.
Alcohol can impair your vision and hearing, it affects your judgement and coordination, while also creating a false sense of confidence.
What is a standard drink?
A standard drink contains about 10 grams of alcohol. The labels on alcoholic drink bottles and cans show the number of standard drinks contained.
What is a Blood Alcohol Concentration?
Blood Alcohol Concentration (or BAC) is the amount of alcohol present in your body and is measured in grams of alcohol per 100 mililitres of blood.
What is a legal BAC?
In South Australia, it is an offence for a fully licenced driver to operate a vehicle if their BAC is equal to or above 0.05. The 0.05 limit also applies if you are acting as a qualified supervising driver to a P1 probationary driver, driving between midnight and 5am. Learner, Provisional or Probationary licence holders, and drivers of public transport and heavy commercial vehicles, must not have a BAC greater than zero.
How to stay below 0.05
There is no simple way to exactly determine your BAC. It will vary depending on your weight, gender, the last time you ate, your age, and the condition of your liver.
The following table is a guide to how many standard drinks you can consume if you wish to keep your BAC below 0.05. These figures assume an empty stomach, a healthy liver and a lean body, and have been rounded down to the nearest whole glass.
The following tips will also help you to keep your BAC below 0.05:
Count your drinks
Drink standard drinks
Eat before you start drinking
Drink slowly and don’t top up drinks
Choose alcohol free drinks as spacers
Your BAC will peak between 20 minutes and in some cases as long as two hours after you have finished your last alcoholic drink.
After a night of heavy drinking your BAC may still exceed the legal limit the following morning.
Women need to be particularly careful when drinking, as their BAC tends to be higher due to their smaller size, blood volume and liver size, increased absorption of alcohol and higher proportion of body fat compared with men.
Reducing your BAC
Time is the only way you will reduce your BAC. Alcohol is eliminated from your body through your liver. Your liver requires approximately one hour to process one standard drink.
Drinking coffee, a cold shower, fresh air, eating or exercise will not reduce your BAC.
If you’re planning on drinking, it’s wise to leave your car and arrange alternate transport, or arrange for one of your group to be the designated driver who agrees to drink minimally or ideally not at all.
To download RAA's fact sheet on alcohol, click here.