Do you know your drinking and driving limit and, more importantly, are you really safe drive, even if you stay under the legal limit?

While walking with my husband and then newborn baby one morning, a four-by-four sped around a corner, hit a curb, flew over a pavement and ploughed through a low fence into a children’s playpark in front of us.

The driver appeared to be more than a little intoxicated.

My husband and I were shocked and angry – what if we had been hit or if there were children in the park?

Who are we to judge?

It’s easy to get angry about drunkards driving, but who are we to judge?

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Even good people make bad choices, like driving home when they should have taken a lift or watching without protesting as a tipsy friend slips into a driver’s seat.

Why risk it

We all know that drinking and driving is a terrible idea, but day after day people do it. And it’s not just irresponsible, thrill-seeking teens either.

In 2015, the World Health Organisation ranked South Africa as having one of the highest rates of alcohol-related road deaths in the world.

Why do people still risk their lives, and the lives of others, by drinking and driving?

A study published in Experimental and Clinical Psychopharmacology may explain it. Researchers compared self-evaluation of alcohol recovery with the actual recovery. What they found is that people think they’re functioning normally even when they are technically still too drunk to drive, simply because alcohol intoxication affects our reasoning and problem-solving abilities.

This proves that, if you’ve been drinking you can’t trust yourself to know if you are able to drive.

Related: Drinking alcohol in late teens linked to liver problems in adulthood

Do you know your limit?

Now I can almost hear you saying, “I know my limit, I can have a drink or two and drive home safely.”

Maybe you can… or maybe you only think you can.

Firstly, let’s talk about what the actual legal limit is.

According to the National Road Traffic Act, the concentration of alcohol in any specimen of breath exhaled must less than 0,24 milligrams per 1 000 millilitres and alcohol in any blood specimen must be less than 0,05 gram per 100 millilitres.

Since most of us don’t have a handy Breathalyzer machine in a car cubbyhole, what does this mean in terms of a number of drinks?

PBK Attorneys did the maths based on one unit of alcohol/10ml of pure alcohol per hour consumed by someone weighing 68kg and found this to be equivalent to:

  • Two-thirds of a beer with 5% alcohol
  • 75ml of red or white wine with an alcohol content of 12% to 14%
  • One 25ml tot of whisky or brandy

So, let’s say you order a glass of wine (which contains an average of 175ml) and drink most of it (about 150ml), you need to wait for at least two hours before you even think of getting into the driver’s seat.

Women have less body water than men and achieve higher concentrations of alcohol in the blood after drinking the same amounts of alcohol. Since the studies on alcohol limits are based on men, as a woman, the legal limit may be too much for you.

Alcohol limits are different for different people

If a 68kg adult needs an hour to process just one of these alcohol servings, factor in more time if you weigh less.

And since the studies on alcohol limits are based on men, even if you weight 68 kgs as a woman, the legal limit may be too much for you.

Sorry ladies, but according to a report on gender differences in alcohol’s effects, women generally have less body water than men of similar body weight, so we achieve higher concentrations of alcohol in the blood after drinking the same amounts of alcohol.

Are you safe within the legal limit?

Let’s pretend that it’s easy to work out and remember your weight/gender to drinks ratio and keep well under the limit while drinking and socialising with friends. If you’re within the legal limit before driving, you should be safe… right?

Not so fast.

Even when you’re under the legal limit you are more likely to cause an accident and be blamed for it than drivers who haven’t been drinking.

This is according to a University of California study of over 500 000 fatal collisions.

The researchers found that even “minimally buzzed” drivers – with a blood alcohol content of 0,01% (remember, the legal limit is 0,05) – are 46% more likely to be officially and solely blamed by accident investigators than are the sober driverswith whom they collide.

The researchers concluded that there is no safe combination of drinking and driving.

One for the road

Sorry to be the Debbie Downer but to sum it all up, even when under the legal limit, driving after drinking alcohol is not safe.

Fortunately, catching a ride is easier than ever before.

Thanks to services like Uber, a sober driver is available via an app. Oh, and if you read the fine print, you may find out that you’re entitled to a few free cab rides through your bank and insurance policies. And of course, you could always enlist a teetotaller friend as a designated driver.

They say that “Everyone should have a lawyer, plumber and doctor as a friend”, but I think we can all agree that adding a teetotaller to the list is not a bad idea either.

Sources: AAExperimental and Clinical PsychopharmacologyNational Institute on Alcohol Abuse and AlcoholismPBK Attorneys, University of California, and the World Health Organisation