Some drivers might think that they are under the limit and fine to drive after drinking one or two alcoholic drinks…But are you really safe to drive?

  • TL;DR: Even one or two drinks can impair driving abilities and increase the risk of collisions. Research shows there is no completely safe level of alcohol consumption for driving. Driving at the legal BAC limit of 0.05% doubles the likelihood of an accident, and beyond this, the risk increases dramatically. Factors like the type of drink, body characteristics, and time can affect alcohol’s impact. Guidelines suggest no more than two standard drinks in the first hour for men, but it’s safest to avoid driving after drinking any alcohol.

You have a drink or two, and you wait around for a minute before heading off in your car. Because they were one standard drink you’re thinking that you’re OK to drive. And even if there’s a bit of alcohol in the system, because you’re under the legal limit for driving on a public road in Australia, it’s ok to drive. But science says there’s no absolute safe level of alcohol consumption for competent/safe driving. Even just one drink is enough to impair your driving ability, affecting things like your ability to see or locate moving lights, judge distances, and you’re more likely to take risks when driving, too[^1][^2].

Drive at the legal limit of 0.05 blood alcohol concentration (BAC) and you’re twice as likely to be involved in a collision than before drinking[^2]. Beyond 0.05 BAC you’re a staggering eight times more likely to be involved in a collision than before you had a drink[^3].

Alcohol hits your brain within minutes of being consumed and hangs around until your body metabolises the alcohol, and the time it takes to do this varies depending on the type of drink you consume, your height, age, size, and sex, the length of time you consumed the alcohol across, whether food was consumed, the health of your liver, and your fitness, etc[^4].

When can I drive after drinking?

The guidelines state that males can drink no more than two standard drinks in the first hour (containing no more than 10g of alcohol each), followed by one standard drink every hour after that[^5]. A standard drink might be 30ml of spirits, 285ml of beer, or 375ml of low-alcohol beer, 100ml of wine, or 60ml of sherry or port.

Effects of drinking and driving

As the alcohol lobs in your brain, the brain’s activity begins to slow down. This is a fact. And this means, if you’re driving a car, that you’ll start focusing on one thing at a time, like steering, but you won’t notice peripheral things, like a child running out onto the street or a car braking ahead of you, or maybe even the traffic lights changing. According to research, a blood alcohol level of 0.02% is enough to see hand shaking appear and thus an inability to control lane position while driving, with the result that the driver is more likely to wander in and out of their lane[^6]. And, as mentioned, perception of what’s occurring around them also diminishes, even if the driver doesn’t realise it[^1][^2].

Drinking and driving statistics

Looking at research data, it seems that when questioned almost no one can accurately predict whether, after one or two drinks, they’re under or over the legal limit. The problem can be compounded by alcohol addiction problems and a numbed sense of its effects[^7]. This has led to various medical professional groups calling for a lowering of the blood alcohol limit from 0.05% to 0.02% and then onto 0%[^8]. But then, research also shows that fatigue and dehydration can be just as affecting as a blood alcohol limit of 0.05%[^9]. Around 15% of collisions in Australia are alcohol-related (but alcohol was the contributing factor in 30% of fatal collisions), while 17% are related to fatigue[^10]. But I digress.

Essentially, just about everyone agrees that while the blood alcohol limit might be 0.05%, there really is no safe level of alcohol you can have in your system and still be ‘fine’ to drive a vehicle. And while I hate to sound like a parent, if you’re planning on drinking, then organise an alternative way of getting home. Don’t risk driving, even after just one drink.


  1. Moskowitz, H., & Fiorentino, D. (2000). A review of the literature on the effects of low doses of alcohol on driving-related skills. National Highway Traffic Safety Administration.
  2. Howat, P., Sleet, D., & Smith, I. (1991). Alcohol and driving: Is the 0.05% blood alcohol concentration limit justified? Drug and Alcohol Review, 10(2), 151-166.
  3. Zador, P. L., Krawchuk, S. A., & Voas, R. B. (2000). Alcohol-related relative risk of driver fatalities and driver involvement in fatal crashes in relation to driver age and gender: An update using 1996 data. Journal of Studies on Alcohol, 61(3), 387-395.
  4. Norberg, Å., Jones, A. W., Hahn, R. G., & Gabrielsson, J. L. (2003). Role of variability in explaining ethanol pharmacokinetics: research and forensic applications. Clinical Pharmacokinetics, 42(1), 1-31.
  5. Australian Government Department of Health. (2020). Australian guidelines to reduce health risks from drinking alcohol.
  6. Howland, J., Rohsenow, D. J., Cote, J., Gomez, B., Mangione, T. W., & Laramie, A. K. (2001). Effects of low-dose alcohol exposure on simulated merchant ship piloting performance. Journal of Studies on Alcohol, 62(5), 569-576.
  7. Hingson, R., Heeren, T., & Winter, M. (1998). Effects of recent 0.08% legal blood alcohol limits on fatal crash involvement. Injury Prevention, 4(2), 144-150.
  8. Fell, J. C., & Voas, R. B. (2006). The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States. Journal of Safety Research, 37(3), 233-243.
  9. Roehrs, T., & Roth, T. (2001). Sleep, sleepiness, and alcohol use. Alcohol Research & Health, 25(2), 101-109.
  10. Czeisler, C. A. (2011). Sleep deficiency and motor vehicle crash risk in the general population. Sleep, 34(3), 307-310.

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  1. Petition the pro-alcohol Government to make the blood alcohol limit 0.00 for all drivers and your column will carry a lot more weight, rather than using the politically-correct mantra “Don’t risk driving even after just one drink.”

  2. Because of so called “safety” we should be locked in our homes and never get out.

    Everything we do in our lifes carries risks. Deal with it. You will never be safe. We as society should discuss to define at what risk guilt is applied. If being tired also causes accidents, does that mean the person is guilt in that scenario because of it, or just if the alcohol was 0.051? Bringing down alcohol to 0.00 as mentioned by John is just plain bad for our liberties as the risk involved in a 0.05 alcohol:blood proportion although increases risks of a collision doesnt do it in such high manners that it should be banned.

    “Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety.”
    Benjamin Franklin

    1. I highly doubt that Ben Franklin meant it was ok to go out and get people killed so you can exercise your right to act like an idiot. You do understand that there were laws in colonial America too don’t you? And that by “liberty” they didn’t mean that everyone had the right to do anything and everything they felt like doing? Don’t confuse liberty with anarchy.

      Of course everything we do in our lives carries risks. There are reasonable risks that we can’t avoid. There are also completely unnecessary risks that come from acting selfish and irresponsible. Just because we have to live with one does not mean we have to pile on the other, at least not when other people’s lives are the ones you’re gambling with.

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