Are you okay to drive? Alcohol impairs your judgement, so how can you really know for sure?

There’s a “rule of thumb” you might have heard about two drinks in the first hour and one every hour after that. Do you really trust yourself to count drinks and keep track of time? Not to mention drinks come in different sizes and alcohol concentration levels, making the counting even trickier.

So how do you know if you are okay to drive? The best way is to avoid driving during the occasions you choose to indulge. Otherwise, you need to understand a little thing called Blood Alcohol Concentration and the legal limit you are allowed to reach.

Let’s dig deeper.

What Are the Legal Limits?

The law must be based on something measurable. When it comes to alcohol intake, it uses your Blood Alcohol Concentration (BAC). This is the level of alcohol present in your blood expressed as a percentage.

For all drivers in Australia, it is illegal to drive if your BAC is over 0.05%. This means that for every 100 ml of blood there is 0.05g of alcohol in your body.

However, though 0.05% is the highest allowed limit, there are two other limits that apply to certain drivers in Australia. You are responsible to know which limit applies to you. According to the experts at Riviere Law, ignorance is not a defence.

If you are driving a public vehicle, such as a taxi or a bus, the limit drops to 0.02%. This limit also applies if you are driving a vehicle carrying dangerous goods or a large vehicle greater than 13.9 tonnes.

Keep in mind that just one standard drink can put some people over the 0.02% limit. Anyone subject to this limit is advised not to drink alcohol before driving to stay on the safe side.

There are also certain drivers who are not allowed to have any alcohol at all in their bloodstream while driving. This zero limit applies to provisional 1 or 2 drivers, learner drivers, and international drivers holding an equivalent license in another country.

When Will I Hit the Limit?

It isn’t enough just to know the legal limits, you also have to know when you’re getting close or have gone over. This gets tricky, especially since the more alcohol you have in your bloodstream, the less clearly you will be thinking.

Plus, there isn’t a hard and fast rule you can follow. We mentioned the rule of thumb earlier which states two standard drinks in the first hour and one every hour after that.

Variable BAC

However, alcohol affects people differently based on various factors. These include:

• * Gender

• * Body composition

• * Liver function

• * Food

• * Alcohol tolerance

• * General wellbeing

Women reach a higher BAC faster than men because they have a higher ratio of fat to lean muscle. A heavier person will be able to tolerate more alcohol than a lighter person. Plus, a person who drinks regularly will develop a tolerance to alcohol and their BAC will rise more slowly.

The same person may even reach the limit faster or slower depending on the day. Having food in the stomach inhibits the absorption of alcohol into the bloodstream, which helps keep your BAC lower. Plus, people tend to reach a higher BAC faster when they are feeling stressed or tired.

In sum, BAC is variable and there isn’t a good way to know how fast you’ll get to the 0.05% limit — unless you walk around with a portable breathalyzer test in your pocket.

Drink Size

Another problem with counting drinks is that there isn’t a good way to know how much alcohol is in each drink you consume. Drink sizes vary, as well as the alcohol content of a given drink.

For example, 350 ml of a typical beer contains 5% alcohol, but 44 ml of a spirit like whisky or vodka contains 40%!

Even if you keep track of how much alcohol is in certain types of drinks, are you mixing your own drinks? Bartenders don’t always measure exactly how much of each spirit they’re putting into a mixed drink.

Staying Safe on the Road

In other words, the only way to know for sure that you’re staying under the limit is to not drink alcohol and then drive your car soon after.

If you want to indulge for an evening, take public transportation or call a taxi. If you’ll be going out with friends, choose one to be the designated driver. There are many ways that you can avoid drinking and driving.

The risk simply isn’t worth it.