You may have been tempted to climb behind the wheel of your car after a post-work glass of wine, or after a couple of beers at your friend’s birthday party.
But do you really know how many drinks you are allowed before you reach the legal drink-driving limit?
Don’t take the risk of hurting others or yourself. Instead, wise up with our drink-driving guide and stay safe this season.
How many drinks am I allowed to stay under the limit?
If your breath alcohol content is more than 35µg of alcohol per 100ml of breath, or you are under the limit but appear out of control in your vehicle, you can still be criminally charged.
How much you can drink to stay under these limits depends on many factors, including:
- your weight, age, sex, metabolism
- what you’ve eaten that day
- the type of alcohol you’re drinking
- the amount you’re drinking
- your stress levels
The truth is, there is no foolproof way to drink and drive safely.
Even a small amount of alcohol can affect your driving ability, so it is always best to avoid drinking entirely when you plan to get behind the wheel. Instead, use public transportation or call a taxi to take you to your destination.
Why can’t I just have a couple of drinks?
0.02% blood alcohol content (approx. 2 drinks per 73kg male)
- Decline in ability to track moving objects
- Decline in ability to multi-task
0.05% blood alcohol content (approx. 3 drinks per 73kg male)
- Decline in ability to track moving objects
- Reduced coordination
- Difficulty steering
- Reduced response time to emergencies
0.08% blood alcohol content (approx. 4 drinks per 73kg male)
- Decline in ability to process information (eg. traffic signals)
- Lack of speed control
- Reduced concentration
- Short-term memory loss
- Impaired perception
0.10% blood alcohol content (approx. 5 drinks per 73kg male)
- Decline in ability to maintain lane position and brake at the right time
0.15% blood alcohol content (approx. 7 drinks per 73kg male)
- Decline in ability to process sights and sounds
- Impaired vehicle control
Note that a standard drink is approximately a 355ml can of beer, half a glass (150ml) of wine, or a shot (44ml) of spirit.
How long does it take for my blood alcohol content to drop? Can I drive the next day?
On average, it takes about an hour for an adult to process 1 unit of alcohol so that there’s none left in their bloodstream. (An alcohol unit is 80mg or 8g of pure alcohol, which is equivalent to 150ml of beer, 76ml of wine or 25ml of spirit.)
However, this is different for everybody. and not a sure-fire way to calculate whether you are under or over the legal drink-driving limit.
If you consume several alcoholic drinks over the course of an evening, you may even still be over the legal drink-driving limit the morning after, as the breakdown of alcohol by enzymes in your body depends on a mix of factors.
There is nothing you can do to make the alcohol disappear from your system quicker, so if you know you need to get behind the wheel the morning after a party:
- Try and limit yourself to no more than 2 standard drinks (men) or 1 standard drink (women)
- Opt for lower strength drinks, eg. 4% or lower beer, 12% or lower wine, single spirit measures
- Alternate alcoholic drinks with soft drinks or water
- Stop drinking well before the end of the night
Other ways to stay safe this holiday season
Drinking doesn’t just impact your ability to drive. While there is nothing wrong with enjoying the occasional drink, abusing alcohol regularly or in large quantities can affect your judgement, lead to dangerous situations and negatively impact your health.
To stay safe this holiday season:
- Check with your doctor to find out if it is safe for you to drink, especially if you have a pre-existing health condition or are taking medication
- Remember to eat a snack or meal before drinking alcohol
- Stay with your friends and don’t wander off alone
- Pay attention to signs of a friend having had too much to drink (slurred speech, unsteady coordination, inappropriate behaviour) and call for help if the situation is urgent
- Drink plenty of water during and after drinking alcohol
Long-term alcohol abuse can have severely damaging effects, such as liver damage, diabetes, ulcers, high blood pressure, stroke, heart attack, infertility or cancer. If you are concerned about your drinking habits or need more advice, do consult your doctor.
Article reviewed by Dr Samuel Low, clinical director at Parkway Hospitals
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