Not to sound like an after-school special, but drinking and driving don’t mix.

Alcohol affects your driving ability in several ways.

Most notably, alcohol:

  • impairs your judgement
  • significantly slows your reaction time
  • makes it hard to focus on driving
  • affects your ability to control the car or speed
  • reduces coordination
  • inhibits your ability to track moving objects

How soon do these effects wear off? What if you’ve had “a few” but feel fine? What if you feel a light buzz but know you’re under the legal limit? Here’s everything you need to know.

Alcohol metabolism rates vary widely between people and situations. In general, your liver can process around 1 ounce of liquor per hour, which is roughly one standard drink.

Keep in mind that boozy beverages aren’t created equal. Some contain more alcohol than others.

Also, what you consider one drink could actually equate to more (sometimes ~a lot~ more) than what’s recognized as a standard drink.

A rough guide

Here are some general estimates on how fast the body metabolizes different drinks:

  • A small shot of liquor: 1 hour
  • A pint of beer: 2 hours
  • A large glass of wine: 3 hours
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Obviously, the more drinks you consume, the longer it’ll take your body to process the alcohol. As a result, you’ll have a higher concentration of alcohol in your blood (more on this in a minute).

The factors that can affect metabolism rate include:

  • Age. Slowed circulation and lower muscle mass as you age affect how alcohol is distributed, metabolized, and eliminated.
  • Biological sex. For several physiological reasons, females metabolize alcohol differently than males and will feel the effects more, even if they’re the same size. Lower body water volume, hormonal factors, and lower levels of a liver enzyme that breaks down alcohol are a few reasons.
  • Body weight. The more a person weighs, the more space through which alcohol can diffuse in the body. The gist being that if you weigh notably less than your friend, the concentration of alcohol in your blood will be higher even if you drink exactly the same amount.
  • Food (empty vs. full stomach). Alcohol is absorbed through the stomach lining. Having food in your stomach slows gastric emptying and reduces the absorption of alcohol. On the flip side, if you drink on an empty stomach (never a good idea), the faster your body absorbs the alcohol, leading to a higher concentration of alcohol in your system.
  • Other substances and medications. Certain medications can affect alcohol metabolism and how you feel alcohol’s effects. Same goes for many recreational substances (not that you should consider driving after consuming any of those, either).
  • How fast you drink. If you’re pounding back shots or chugging your drinks, you’re not giving your liver the time it needs to process the alcohol. This means longer lasting effects.

Blood alcohol concentration (BAC) determines not only how drunk you feel, but whether you’re legally considered too impaired to drive.

BAC is determined by the amount of alcohol in the blood compared to the amount of water in the blood.

A BAC of .08 grams of alcohol per deciliter (g/dL) or higher is above the legal limit in the United States. But don’t let that number guide your choice to get behind the wheel.

First, .08 g/dL is actually a bit higher than the .05 g/dL limit used by many European countries.

Also, your driving skills can be affected even if you’re well under the legal limit, which could also result in legal problems.

As a matter of fact, the National Highway Traffic Safety Administration reported that in 2018, 1,878 people were killed in alcohol-related crashes involving drivers with BACs below the legal limit in the United States.

If you’ve landed here because you’re looking for a way to test if you’re sober enough to drive, you’re out of luck.

There’s really no reliable way to self-test your ability to drive safely after drinking, even with a sleekly designed app on your phone.

Alcohol affects your judgement, so you’d be in no position to evaluate your driving skills — or anyone else’s, for that matter — after drinking.

You could use a personal breathalyzer, but it can only tell you what your BAC is. (Remember, your BAC is just a number. Having a legal BAC reading doesn’t necessarily mean it’s safe for you to drive.)

Alcohol affects everyone differently, so while some may be able to function normally and drive safely at the legal limit, plenty of others can’t.

The safest thing you can do is not get behind the wheel after you’ve been drinking.

How do you sober up faster? You don’t. Sorry.

The internet is full of advice and miracle potions that claim to help you sober up faster, but none of these work or have any kind of scientific evidence to back them up.

The only thing that lowers your BAC is time, and how long that takes is individual to the person and the circumstances.

The best you can do is wait it out, or not let your BAC get high in the first place.

Doing the following can help you keep alcohol from impairing your ability to drive the next time you drink:

  • Decide on a limit of how many drinks you consume in one sitting before you start drinking.
  • Give your body time to process the alcohol by sipping (not gulping) your drinks and alternating with nonalcoholic drinks.
  • Stick with drinks with a lower alcohol content.
  • Have something to eat before you drink, and nibble on snacks while you’re drinking.

If you’re not sure whether it’s safe for you to drive, err on the side of caution and don’t drive.

With someone dying in a drunk driving accident every 50 minutes in the United States, your safest bet is to not get behind the wheel after drinking.

Make other arrangements for a ride home before drinking, or take the time to sleep it off before driving.

Adrienne Santos-Longhurst is a Canada-based freelance writer and author who has written extensively on all things health and lifestyle for more than a decade. When she’s not holed-up in her writing shed researching an article or off interviewing health professionals, she can be found frolicking around her beach town with husband and dogs in tow or splashing about the lake trying to master the stand-up paddle board.