How do breath tests work?

After having a couple of drinks you may feel fine, so you get into your car and head home. Next thing you know, flashing lights and sirens appear behind you. When the officer comes to the window to talk to you, you suddenly become concerned because your breath may smell like alcohol. Then the officer asks you to step out of the vehicle and submit to a breath test.

How often have you heard similar stories from your friends or family members? More than likely, anytime a discussion about drunk driving comes up, these little machines are mentioned. So, how exactly do alcohol breath tests work?

Here’s what happens when you drink alcohol

In order to understand how breath-testing machines work, you first need to understand what happens when you drink alcohol:

  • Alcohol hits your stomach and small intestine
  • Oxygenated blood absorbs the alcohol
  • Alcohol moves through the body to the lungs and brain
  • Alcohol in the lungs is expelled when exhaled

Your breath now contains a certain amount of alcohol. How quickly this process occurs depends on a number of factors, such as the following:

  • How much you drank
  • The last time you ate
  • Your weight
  • Your gender

Your blood alcohol content, or BAC, tends to peak approximately one hour after drinking alcohol.

What does the breath-testing machine do?

Your liver breaks down approximately 90 percent of the alcohol you ingest. The remaining 10 percent leaves your body through your urine and your breath. A breath-testing machine calculates the concentration of alcohol in your blood and turns it into a BAC measurement. If that measurement reaches or exceeds .08, the officer could arrest you for drunk driving.

Why is the legal limit in Colorado .08?

The National Highway Traffic Safety Administration conducted numerous studies to determine how alcohol affects the ability to drive. It then concluded that at .08, your driving ability becomes significantly impaired. Of course, that limit applies to adults. For anyone under the legal drinking age of 21, the BAC is much lower.

Can breath tests be wrong?

Yes. Any number of factors can cause a false positive. In addition, the timing of the test can also affect its results. If an officer arrests you for DUI based on a breath test, you do not have to simply accept your fate. A thorough review of the circumstances surrounding the breath test, your physical condition and the condition of the machine itself could reveal that your results were less than accurate.

Furthermore, an attorney will also review the totality of the situation. From the moment you pull over for a police officer, you have rights. Any violation of those rights could result in a dismissal of the charges. In the alternative, you could have options other than a conviction, depending on the circumstances. Seeking the advice and assistance of an attorney right away could keep a DUI from significantly impacting your life.

Cynthia A. McKedy

Criminal Defense Attorney Cynthia A. McKedyAs a former prosecutor, Ms. McKedy supervised and trained new deputy district attorneys. During her tenure as deputy district attorney, Ms. McKedy successfully tried over a dozen homicide cases. As a defense attorney, she has been able to utilize all of her trial skills and knowledge to procure great results for her clients.

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2018-11-05T12:48:23-06:00August 14th, 2017|DUI|