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Published on 3/6/2023, 4:34:00 PM

Challenging Breathalyzer Results in Maryland DUI Cases, Can we beat my breath test?

If you have been charged with a DUI in Maryland, one of the main pieces of evidence the prosecution may use against you is the results of your breathalyzer test. In Maryland, a driver is considered to be driving under the influence (DUI) if their breath alcohol result gives a blood alcohol content (BAC) of .08 or higher. This leaves many clients asking, "If I blow over .08 am I automatically guilty?"

No, it is important to understand that breathalyzer results are not always accurate and can be challenged in court. If you have been charged with a DUI in Maryland and your breathalyzer results were used as evidence, it is crucial to know your rights and options for challenging these results.

What do the results mean?

Breathalyzer results are meant to measure the amount of alcohol in a person's breath and estimate their blood alcohol content (BAC). In Maryland, if a driver's BAC is .08 or higher, they are considered to be driving under the influence. However, it is important to note that breathalyzer results are not always accurate and can be affected by a number of factors, including:

Are these machines 100% Accurate?

Even Maryland law knows, that this machines have a degree of inaccuracy built into them. The breath testing machines emplyoed by the State must be annually reviewed and certified by the Maryland State Toxicologist. When this re-certification happens, a deviation under 10% between the results is acceptable. Thus - it is entirely possible that these machines can be up to 10% inaccurate without being de-certified.

Calibration of the Machine

Breathalyzer machines must be calibrated properly to ensure accurate results. If the machine is not calibrated correctly, the test results may be inaccurate. Between each test the machine performs a "system check". If this check fails, that could result in an inaccurate blow.

Reasons for an Inaccurate Blow

There are a number of reasons why a breathalyzer test may produce inaccurate results.

For example, if the driver has a medical condition that affects their breathing, had extensive dental work trapping alcohol in their mouth, or if they have recently used mouthwash or other substances that can affect the test results, the breathalyzer results may be inaccurate.

There are strict protocols for the administration of a breath alcohol test. These include a mandatory twenty minute observation period. If alcohol is reintroduced into the mouth during this period via burping, or other means, then the test may be tainted.

What are the test procedures?

Below is a portion of the staute that regulates breath samples:

For at least 20 minutes before a breath sample is taken, an individual may not:

  • Eat or drink;
  • Have any foreign substance in the individual's mouth or respiratory tract; or
  • Smoke.

The individual shall be observed and mouth checked.

Observation of the individual shall be performed by:

  • A breath test operator;
  • Other uniformed or civilian law enforcement personnel;

The testing procedure shall begin with a blank test to ensure that no alcohol is present in the breath path of the breath testing instrument.

  • A validation test shall be run before the individual begins the testing process.
  • If the breath testing instrument fails to obtain a reading plus or minus 10 percent of the stated alcohol concentration on the validation test, then the subject test shall be discontinued.
  1. The individual shall be instructed to take a breath and then deliver a breath sample into the instrument by blowing into the mouthpiece and breath tube until instructed to stop.
  2. After each subject breath sample, a blank check shall be performed to ensure that no alcohol is present in the breath path.
  3. Two breath samples shall be collected and analyzed by the breath testing instrument.

Source: Md. Code Regs. 10.35.02.08

What if my breath samples are very different?

If your breath samples are very different, it may indicate that the machine is not working properly or that there is some other issue with the test. An experienced criminal defense attorney can help you challenge the accuracy of your breathalyzer results and work to have them suppressed as evidence.

According to Maryland Statutes, a third breath sample should be required if there is over a 10% difference between the two samples you give during a breath test.

What do they prove?

Breathalyzer results are not always a reliable indicator of a person's BAC or whether they were under the influence while driving. In some cases, the results may be inaccurate or may not provide a complete picture of the situation. For example, a driver may have had a drink right before getting behind the wheel, but their BAC may not have been at the legal limit when they were actually driving.

DUI Per Se in Maryland

In Maryland, a driver is considered to be driving under the influence (DUI) if their BAC is .08 or higher. This is known as a "per se" DUI offense, which means that the prosecution does not have to prove that the driver was actually impaired while driving. However, even if a driver's BAC is above the legal limit, it does not necessarily mean that they were under the influence while driving.

Expert Witnesses Generally

Expert witnesses can be an important part of challenging breathalyzer results in Maryland DUI cases. An expert witness is a person who has specialized knowledge or expertise in a particular area and can provide testimony in court. In DUI cases, the State has to offer their breath technician as an expert witness. The Defense may call an expert witness to challenge the accuracy of the breathalyzer results and provide an alternative explanation for the driver's behavior.

Expert witnesses must be qualified for their expertise and can be challenged by attorneys for the Defense and State.

Intoximeter Machine:

The Intoximeter EC/IR II is the most common breathalyzer machine used in Maryland. It uses infrared spectroscopy to analyze the alcohol content in a breath sample. The machine requires regular calibration and maintenance to ensure accurate results. In some cases, a defense attorney may challenge the accuracy of the machine or the calibration process if they suspect that the results are incorrect.

Standard Deviation:

The standard deviation is a measure of the variability of the results of a breathalyzer test. A high standard deviation may indicate that the machine is not functioning correctly or that the breath technician did not administer the test correctly. A defense attorney may use the standard deviation to argue that the results of the test are unreliable and should not be used as evidence in court.

Reasons for an inaccurate blow:

There are many factors that can contribute to inaccurate breathalyzer results. For example, if the person being tested has certain medical conditions or has recently consumed certain foods or drinks, it may affect the results of the test.

  • The breathalyzer machine may not be functioning correctly, or the breath technician may not have followed proper procedures when administering the test.

  • Calibration of the Machine: To ensure accurate results, breathalyzer machines must be regularly calibrated and maintained. If a defense attorney suspects that the machine was not properly calibrated, they may challenge the results of the test.

What is the Standard or "STD" in my breath test:

The standard, or "STD," is a substance certified by the Maryland State Toxicologist. It is used to calculate the margin of error in the test results, and it should read exactly .08 on the Machine's results. A higher STD result may indicate that the machine is less precise, which could affect the accuracy of the test results.

What if my breath samples are very different?

If the two breath samples taken during a breathalyzer test are very different from each other, it may indicate that the machine is not functioning correctly or that the breath technician did not administer the test correctly. A defense attorney may use this discrepancy to argue that the results of the test are unreliable and should not be used as evidence in court.

Why did they drop the third digit on my breath result?

The third digit on a breathalyzer test result is often dropped because it is not considered significant enough to affect the overall accuracy of the test results.

Fight your DUI today

If you have been charged with a DUI in Maryland, it is important to seek the advice of an experienced criminal defense attorney. An attorney can help you understand your legal rights and options and can work to build a strong defense against the charges. With the right legal representation, it may be possible to challenge the results of a breathalyzer test and potentially have the charges against you reduced or dismissed. Contact us today