Can only one beer put you over the legal limit for driving, a blood alcohol content (BAC) level at or above 0.08 percent? “It depends” is the only honest answer. It depends on things like your weight. Are you male or female? When did you last eat, what did you eat, and how much? Are you taking any medications? And how long ago was the one beer? These are just a few of the factors that can impact your BAC level. When you understand some of the basic science behind DUI law – about how alcohol interacts with your body and impacts your ability to drive – you can apply that knowledge and be a smarter, safer driver.


Measuring the amount of alcohol in someone’s blood can be compared to measuring the amount of gasoline in an automobile’s gas tank. The amount of gasoline in a tank depends on how often the tank is refilled and on how much gas is burned driving the vehicle. Similarly, the amount of alcohol in the blood is the balance between how much alcohol is absorbed into the bloodstream and how fast that alcohol is burned off or excreted as waste. The body burns alcohol at a more-or-less steady rate, so the key is how much alcohol someone drinks and how fast that person drinks it.


When someone drinks, alcohol enters the bloodstream through the mucous lining of the gastrointestinal tract. The absorption rate increases as alcohol descends through the tract. Alcohol absorption from the stomach into the bloodstream – through capillaries in the stomach lining – can be fast. Drinking on an empty stomach can get someone drunk quite quickly because there is nothing else “competing” to be absorbed into the blood.


About sixty percent of the alcohol that a theoretical “average person” drinks will be absorbed into the bloodstream in thirty minutes. About ninety percent is absorbed in an hour, and all of it is absorbed in ninety minutes. Remember, however, that the actual rate of alcohol absorption in real life depends on all sorts of things: the quantity of alcohol, the pace of drinking, and the nature and amount of any other material in the stomach.


The body eliminates alcohol in two ways. Ninety to ninety-five percent of the alcohol is oxidized (“burned off”) in the liver to form water and carbon dioxide. The rate of oxidation depends on the health of the liver. People who drink regularly burn alcohol faster than casual drinkers, and chronic alcoholics burn it even faster. The remaining alcohol is eliminated by perspiration, in urine, and through the breath.

Because driving with a BAC level at or above 0.08 percent is illegal, it can be helpful to estimate your own blood alcohol content level based on the amount of alcohol you drink and the amount of time you take to drink it. Although it may be impossible to determine your precise BAC level without a breathalyzer, there is a simple formula for estimating what your highest possible blood alcohol content level could be.


Here’s the formula: Divide the number 3.8 by your body weight in pounds. You’ll get a number between 0.015 and 0.40. Call this your “blood-alcohol maximum-per-drink” number. This is the maximum percentage of alcohol that is added to your bloodstream by each drink. For this formula, a “drink” is a 12-ounce bottle of beer, a 4-ounce glass of wine, or a one-ounce shot glass of 100-proof liquor. Microbrewery beer, malt liquor, pint bottles of beer, large wine glasses, “fortified” wines, and larger mixed drinks should be counted as 1½ drinks.

Juanita, for example, at one hundred pounds, could have a BAC level of 0.038 percent after one drink and a BAC level of 0.076 percent after just two. Three drinks would put her over the limit, especially if she drinks fast on an empty stomach. Boris, on the other hand, at 240 pounds, has a maximum BAC level increase per drink of only 0.016. To get to the 0.08 percent BAC level limit for driving, Boris would have to consume at least six drinks within sixty minutes.

Some people can get themselves intoxicated quite quickly, but how quickly is alcohol eliminated from the body? About forty minutes after drinking, the body starts oxidizing alcohol from the bloodstream at a rate of approximately 0.01 percent for each additional 40 minutes. So, when you multiply the number of drinks by your “blood-alcohol maximum-per-drink” number, you then subtract 0.01 percent from that number for every forty minutes since you began drinking – but don’t count the first forty. If you can’t do the calculation, it’s likely that you are too intoxicated to drive.


A recent technological advance that may – or may not – be helpful is the smartphone breathalyzer. Several are now on the market with names like Alcohoot, BACtrack, and the Breathometer. Manufacturers of these devices make no claim for their accuracy. A commercial breathalyzer may provide a rough estimate of someone’s BAC level, but commercial breathalyzers are not accurate enough to tell you with certainty whether or not you should drive. Fortunately, each mobile breathalyzer app also features the ability to call a taxi, and some even offer directions to nearby hotels.


Of course, to be truly safe, it’s genuinely best not to drink and drive at all, and you certainly should never “guess” about your BAC level or drive if you have any doubt whatsoever. Particularly in the Las Vegas area, taxis, limousines, car services, buses, and courtesy vans are abundant and available 24 hours a day, so there’s never an excuse for driving under the influence in Las Vegas. Anyone arrested and charged with DUI in Nevada could face serious penalties and will need legal help from an experienced Las Vegas DUI lawyer. A conviction for a first-offense DUI in Nevada is punishable by:

  • a fine of $400 to $1,000 and additional legal costs
  • two days to six months in jail or up to ninety-six hours of community service
  • attendance at a DUI/alcohol awareness class and you pay the “tuition”
  • a ninety-day driver’s license suspension
  • participation in a Nevada Victim Impact Panel

If anyone does end up charged with DUI in the Las Vegas area – despite his or her best efforts to drive safety and to avoid driving while intoxicated – an experienced Las Vegas DUI lawyer can provide the legal assistance that person needs. But with your “personal BAC formula” and a better understanding of the science behind DUI law, you should be able to drive safely in the Las Vegas area – or anywhere else – and entirely avoid DUI-related legal trouble.