Drinking and Driving: Two Drinks can be Too Many

DUIAn interesting conversation was had last week over a few pints of beer about Blood Alcohol Contents, Drinking and Driving and How to be Safe when out for a night on the town.

Short answer, do not drink and drive when out.

In order to get a better understanding of the issue I have guest author Richard Jacobs who is the chief editor of MyDUIattorney, to put an end to the confusion once and for all.

Richard, take it away…


The Two Drink Rule: true or false?

If you are aware of drinking and driving, you must have heard of the “Two Drink Rule”, which people use to determine whether they can drive back home from a bar, pub or party safely or not. A lot of people make the mistake of following this rule by assuming that having two drinks will keep them under the legal limit of 0.08 and they can safely reach home. This is what can get them in trouble.

If you are driving back home after having a couple of drinks and happen to pass through a DUI checkpoint or are stopped by a police officer as a DUI suspect, you will be asked to submit to a breathalyzer test.

Regardless of your individual tolerance to alcohol, two drinks can be more than enough to make you blow a 0.08 or greater on the breath test. Not realizing you were over the legal limit, you might utter something like, “But I only had two beers, Officer!” in disbelief.

However, the fact that you did not realize your were over the allowed legal limit for BAC is not a valid defense for DUI/DWI and will lead to a DUI charge. In order to avoid such a situation, you need to understand what blood alcohol content or blood alcohol concentration (BAC) is and how it works.

How our Body Metabolizes Alcohol

The amount of alcohol you consume directly affects your blood alcohol concentration, regardless of the number of drinks you have had. All states have implemented a per se limit of 0.08 BAC, which means that irrespective of your individual tolerance, you will be charged with drunk driving if you have a BAC of 0.08 or more.

The amount of alcohol in the blood does not depend on the number of drinks you’ve had, but it depends on the amount of alcohol consumed in a specific time period. BAC also depends on the rate at which alcohol is absorbed into the blood stream and will depend on several factors such as sex, weight, percentage of body fat, fitness-level, tolerance-level and how much you’ve had to eat.

Since so many factors are involved in calculating BAC levels, it is very likely that the same sized glass of wine taken by two different people at the same time could lead to very different BAC levels.

To make things easy for you, you can use our BAC calculator to help you get a rough estimate of BAC levels.

Irrespective of the fact how BAC levels are affected, the rate at which alcohol is metabolized and eliminated from the human body is fairly consistent, which is on average 0.015 per hour. This means that anyone with a BAC of 0.15 will take ten hours to get it all out of their system.

So if you decide to go home after the bar shuts at 2am with a 0.15 BAC level, and intend to drive to work the next morning after 5 hours of sleep, you could still be over the limit.

The concept that you can “sleep it off” is totally false as sleep has zero effect on how quickly alcohol is expelled from the body. You may not be feeling drunk the next morning, but you may still have a blood alcohol concentration over the allowed legal limit.

Most people believe that they can “sober up faster” by drinking coffee, eating a big meal, taking aspirin, drinking lots of water or caffeinated soda, but these are big misconceptions. These things can help you feel more sober, but they will have zero affect on your BAC level.

Only time will make the difference in your blood alcohol levels.


Variation in the Amount of Alcohol Contained in Drinks

When drinking at a bar, restaurant or pub, you have to understand that the amount of alcohol in a drink varies per serving. It depends on how much tequila, triple sec or other strong liquors were used in making the drink, which is impossible to measure.

Many bars and restaurants offer small and large glass sizes, but precise serving sizes are never measured. In fact, many bars and restaurants take a “free pour” approach to serving alcohol. Depending on how strong the beer was, you can be way above the legal limit after just one drink.

To help you understand how the blood alcohol content levels vary with weight and the number of drinks consumed, we have included the following reference chart. The chart only takes into account two factors which include the number of drinks and weight. Other factors will influence your BAC levels, which means you could have lower or higher BAC levels than the ones given below.

The safest rule to follow is to not drink and drive.

A standard drink is:

  • 12-ounce bottle or can of regular beer
  • 5-ounce glass of wine
  • drink of one and 1/2 ounce of 80 proof distilled spirits (either straight or in a mixed drink)

Blood Alcohol Content Chart
Use the chart to get an estimate of your BAC level, depending on your weight and the number of drinks consumed. Once you find the estimated BAC, subtract the percent of alcohol eliminated during the time elapsed since you started drinking.


  • For a 200 lb. man who has had 6 drinks, his BAC after 2 hours will be:
  • 113% minus (.015×2) = .083 % which is above the legal limit

Again, to avoid any misfortune, your safest option is to not drink and drive at all!

Be safe,

Richard Jacobs

Author Bio

Richard Jacobs is a chief editor since early 2007, and currently works for MyDUIattorney. A website that helps you to find the right DUI Attorney, you can search for a New Jersey DWI Lawyer online, anytime!

And now you have the truth about drinking and driving.

Thanks again to Richard for taking time to answer these questions.

Be safe and make smart choices,


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