The Truth About Blood Alcohol Content aka BAC

A DrinkingAndDriving.Org Lesson

BAC is the Standard

BAC Stands for Blood Alcohol Content (or Concentration).  When you drink alcohol, it gets passed directly into your bloodstream. BAC can be measured reliably and accurately.  Effects on skills related to driving are very well documented.

Most of the planet is in agreement that driving with a BAC of .08 is too dangerous to allow. This is why laws everywhere are written with .08 or lower as the point of legal intoxication.

At a .08, you experience sedation, slow reaction time, and poor coordination.  It's obvious why driving with a .08 is illegal.

At lower levels, sedation and slow reaction time are still factors.  It's obvious why driving with lower BAC levels is still dangerous.

The ONLY safe BAC level for driving is .00

If you've been drinking, the only way to get to .00 is to wait at least 45 minutes per drink. 

At .05 you can face criminal penalties in most states

It can take over 2 hours to drop from .05 to .00

You are considered Legally Intoxicated at a BAC of .08

That's pretty much just in North America.  Most of the world has set even lower thresholds over the past decade, ranging from zero tolerance to .05 as the legal limit for driving. America is likely to follow suit.

It can take up to 6 hours for your BAC level to drop from a .08 to a .00

If you are under 21, driving with anything higher than .00 is illegal. 

There is only one way down

clock face with 45 minutes highlightedOnce alcohol mixes with your blood, there is only one way to get it out of there.  You have to wait.

A common guideline is that after each typical drink, you must wait 45 minutes before attempting to drive.

If you have another drink, you must add another 45 minutes.

You've had a drink and must wait 45 minutes before driving.  A quarter hour later, you have another drink.  Now you must wait 45 minutes PLUS the 30 minutes left over from the first drink.  That's one and a quarter hours before you should drive.  Got time for another?

Ladies' Night

Because men and women are built differently, women reach a higher BAC drink after drink than men.

More of the alcohol a woman drinks enters her bloodstream.

The first drink or two are not drastically different and the 45 minute rule should be OK.

If you are having the equivalent of 3 or more drinks, You should add another hour to your wait.


We can't say it enough.  After drinking, WAIT before driving.  For more details read our Blood Alcohol Content article.


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