If police pull you over and suspect you of drinking and driving, they’re going to want to do a few tests to make sure you’re over the legal limit of .08. You may be asked to do field sobriety tests like walk a straight line, recite the alphabet backwards or forwards, or even put your finger to your nose, and you’ll most likely be asked to provide a breath sample for a Breathalyzer device.
Breathalyzers are used to measure your blood alcohol levels (BAC). To get an accurate assessment of your BAC, all you have to do is blow into the device for a set period of time and it will let the officer know if you’re over the limit. But how do Breathalyzers work exactly, and how can they be trusted to determine your BAC?
When you drink alcohol, it is absorbed through your mouth, moves into your throat, onto your stomach, and then travels down your intestine into your bloodstream. During that process, some alcohol will move into the membranes of your lungs where it will evaporate into the air when you exhale.
Because the amount of alcohol in the air you exhale from your lungs is directly related to the amount of alcohol in your blood, the Breathalyzer can use that air to measure your blood alcohol level. The actual ratio of breath alcohol to blood alcohol is said to be 2,100:1 – meaning that 2,100 milliliters of air from your lungs has the same amount of alcohol as 1 ml of your blood.
Police Breathalyzers are extremely accurate, and although there are personal Breathalyzers available on the market now that will test your blood alcohol level for you, be cautious when using them. Even though the legal limit is .08, you can be legally intoxicated and have impaired driving ability at .05 or less. Your best option to avoid drinking and driving charges is to not drive, after even just one drink.