Do you know your limit when it comes to drinking and driving? If you think, like many people, that it’s two standard drinks then think again.

A lot of people still think that if they drink two drinks and one every hour after that, they can still drive.

But your blood alcohol concentration level can vary greatly depending upon factors including your height, weight, gender, liver function, fitness and health.

What is the Blood Alcohol Concentration Limit?

The blood alcohol concentration (BAC) limit is the amount of alcohol you are legally allowed to have in your bloodstream while driving. The limit is different for different types of licensed drivers.

Your BAC measures the amount of alcohol you have in your system in grams of alcohol per 100 millilitres of blood. A BAC of 0.05 means you have 0.05 grams (50 milligrams) of alcohol in every 100 millilitres of blood.

In NSW there are three limits zero (for learners, P-Platers and others), under 0.02 (professional drivers) and under 0.05 for the majority of fully-licensed drivers.The limit that applies to you depends on the category of your licence and the type of vehicle you are driving.

What are the factors that can affect your BAC?

There are a range of factors that can affect your blood alcohol concentration level, meaning that two people drinking the same amount of alcohol can have a completely different reading. Some of the factors include:

• Size and weight – a larger person will have a lower BAC than a smaller person drinking the same amount of alcohol
• Gender – men will generally have a lower BAC than women of a similar height and weight
• Liver function – if your liver is not at its healthiest, then it will process alcohol slower than a healthy liver
• Lack of food – Drinking on an empty stomach will mean that alcohol gets absorbed faster in your bloodstream
• Fitness and Health – your BAC can be higher if you are not feeling well, you are tired, stressed or unfit.

What are the Penalties for Drink Driving Offences?

There are serious penalties for drink driving offences in NSW including fines, loss of demerit points loss of licence and imprisonment for more serious offences. See here for a table outlining the maximum penalties for a range of drink driving offfences.

Drinking and Driving Don’t Mix

The best bet is not to drive at all if you’re drinking. If you do want to enjoy a drink, just leave your car behind and ride with a friend, catch a cab or take public transport instead.