Challenging a DUI Breathalyzer Test: Legal Options Explained

If you are arrested and charged with driving under the influence (DUI) in Nevada, you will likely be asked to submit to a chemical breath test, commonly referred to as a “breathalyzer.” The results of that test may be used against you in court to help convict you of DUI. What you may not realize, however, is that breathalyzers are not infallible, meaning challenging a DUI breathalyzer is possible.

Challenging a DUI in Las Vegas - The Vegas Lawyers

Nevada DUI Laws: Why Is Blood Alcohol Concentration (BAC) Important?

Historically, state DUI laws simply made it illegal to drive “while under the influence” or “while impaired.” Proving that someone was “under the influence” or “impaired” often proved challenging for prosecutors, resulting in a high rate of acquittals. With the advent of the breathalyzer, which is a brand name for a chemical breath test machine, states began to change their laws to include a presumption that a motorist is driving while under the influence if the motorist has a blood alcohol concentration (BAC) over 0.08 percent. Nevada law makes it illegal to operate or control a vehicle with a concentration of alcohol of 0.08 or more.

What Is a Breathalyzer?

Before the invention of the DUI breathalyzer test, a blood test was the only reliable way to test a person’s blood alcohol concentration. A blood test; however, is invasive, costly, and time-consuming. There is a direct relationship between the concentration of alcohol in your lungs and the concentration present in your blood, allowing a breath test machine to accomplish essentially the same thing as a blood test by testing your exhaled breath and applying a partition ratio using a complex chemical reaction. The alcohol vapor in your breath reacts with an orange solution known as potassium dichromate, turning the solution green. This color change creates an electrical current, which the breathalyzer can convert into a value that then provides a BAC.

Do I Have to Submit to a Chemical Breath Test in Nevada?

Nevada, like most states, has an implied consent law that effectively says that by operating a motor vehicle within the state you have given your consent to a chemical test if a law enforcement officer suspects you of driving under the influence. If you refuse a breath test, your driving privileges will be suspended for one year in addition to any suspension imposed by the court if you are ultimately convicted of DUI. Furthermore, Nevada law allows a law enforcement officer to use “reasonable force” to conduct a blood test if you refuse to submit to a breath test. Your refusal can also be admitted as evidence and used against you at trial to convince a judge or jury that you were driving under the influence.

Can I Challenge the Results of a Breathalyzer in Nevada?

Under perfect conditions, scientific studies have shown breath test machines to be fairly accurate at measuring a person’s blood alcohol concentration. Perfect conditions, however, rarely exist in the real world, meaning that DUI breathalyzer test results may not be as accurate as the prosecution would like the judge or jury to believe. In fact, there are numerous grounds on which the result of a chemical breath test may be challenged, including:

  • Improperly calibrated machine: For a breath test machine to work properly it must be inspected and calibrated on a regular basis. A machine that has not been recently calibrated may not provide accurate results.
  • User error: Administering a DUI breathalyzer test requires specialized training. If the operator lacks that training the results may be challenged.
  • Failing to follow procedures: Very precise procedures must be followed when performing a chemical breath test, including observing the suspect for the required waiting period prior to administering the test.
  • Rising blood alcohol content: The amount of alcohol in your blood continues to rise after you ingest your last drink. Sometimes a successful argument can be made that even though the results of your breath test showed your BAC was above 0.08, it would not have been above 0.08 at the time you were operating the vehicle.
  • Medications: Certain medications can interfere with the accuracy of a chemical breath test.

What Should I Do If I Was Arrested for DUI in Las Vegas?

If you were arrested and charged with DUI in Las Vegas, consult with a criminal defense attorney at The Vegas Lawyers as soon as possible to discuss your next steps. Call us at 702-707-7000 or contact us online.