How Can You Challenge Breathalyzer Results in a DWI Case?
Facing a DWI (Driving While Intoxicated) charge can be an overwhelming experience. One of the most intimidating pieces of evidence in these cases is the breathalyzer test. These tests are often perceived as foolproof indicators of intoxication, but the truth is far more complicated. Breathalyzer results aren’t infallible, and there are several legal ways to challenge them.
At Danford Law Firm, we help clients understand their options for challenging breathalyzer results in DWI cases. Here, we’ll explain some of those options, what defenses might apply to different situations, and why hiring our Texas DWI defense firm is essential for your case. Contact us today to discuss your rights and options.
The Basics of Breathalyzer Tests
Before challenging breathalyzer results, it’s important to understand the basics of these tests. A breathalyzer is a device used by law enforcement to measure the amount of alcohol in a person’s breath, which is then used to estimate their blood alcohol concentration (BAC). There are two types of breathalyzer tests commonly used:
Preliminary breath tests (PBTs): Conducted on the roadside with handheld devices. These are typically used to establish probable cause.
Evidential breath tests: Performed at the police station with more sophisticated equipment. These results are used as evidence in court.
Despite their widespread use, breathalyzer tests aren’t without flaws. Many factors can lead to false positives or inaccurate readings. Environmental conditions, user error, and even the presence of certain substances in a person’s breath can affect the results. Because these tests estimate blood alcohol content indirectly, they must be scrutinized carefully in any DWI case.
Legal Grounds for Challenging Breathalyzer Results
There are several legal avenues for challenging breathalyzer results in a DWI case. These defenses often rely on uncovering procedural errors, equipment malfunctions, or biological factors that may have skewed the results. Keep reading to learn some of the most common defenses an experienced defense attorney might use.
Improper Calibration or Maintenance of the Device
Breathalyzer machines must be regularly calibrated and properly maintained to allow for accurate readings. If the device wasn’t calibrated according to the manufacturer’s instructions or state requirements, its results may be unreliable. Even slight deviations from calibration procedures can produce BAC readings that are different from your actual level of intoxication.
Your attorney can request maintenance logs and calibration records for the device used in your arrest. If any issues are discovered, such as expired certifications, skipped maintenance, or calibration errors, those breathalyzer results can potentially be thrown out. This type of technical evidence can be critical in undermining the prosecution’s case and strengthening your defense.
Operator Error
Even if the device itself is functioning correctly, the results may be inaccurate if the officer administering the test didn’t follow proper procedures. Police officers must be trained and certified to operate breathalyzers. Errors in how the test is administered can significantly affect the outcome. Evidence of operator error can call the entire test result into question.
Medical Conditions or External Factors
Certain medical conditions can affect breathalyzer readings. Although breathalyzers are designed to detect alcohol in the breath, they can’t always distinguish between alcohol and other substances with similar chemical properties. As a result, individuals with specific health conditions may produce samples that register inaccurately high BAC levels. For example:
GERD (Gastroesophageal Reflux Disease) and acid reflux can cause alcohol from the stomach to be present in the mouth, leading to falsely elevated results.
Diabetics experiencing ketoacidosis may produce acetone in their breath, which some breathalyzers can mistake for alcohol.
Exposure to certain chemicals or solvents (like paint fumes or cleaning agents) can also interfere with the accuracy of breathalyzer results.
If you have a medical condition or were exposed to any substances that could have skewed the results, this can serve as a valid defense. Your attorney may consult with medical professionals or toxicologists to provide testimony supporting your claim. Contact Danford Law Firm today if you think medical conditions may have affected your breathalyzer results.
Mouth Alcohol Contamination
Breathalyzer tests are designed to measure deep lung air, not alcohol present in the mouth. If a person burps, vomits, or uses mouthwash shortly before taking the test, residual alcohol in the mouth can lead to a falsely high BAC reading. This residual alcohol can linger for several minutes and significantly distort the test outcome.
Officers are required to observe a suspect for a period of time before administering a breath test to make sure no mouth alcohol is present. Failure to observe this protocol may be grounds for dismissal of the breathalyzer results. Strict adherence to this observation period is essential to maintain the integrity of the test.
Timing of the Test
Alcohol takes time to absorb into the bloodstream. If you consumed alcohol shortly before being pulled over, your BAC may not have reached its peak at the time of driving, but could be higher when the breathalyzer test was administered later. This phenomenon is known as "rising BAC" and can unfairly incriminate drivers who weren’t actually impaired behind the wheel.
This means the results may not accurately reflect your BAC at the actual time you were operating the vehicle. Your defense attorney can use special witnesses or toxicology reports to argue that the breathalyzer results are misleading based on the timing. Such arguments can be especially persuasive in court when supported by credible scientific analysis.
Violation of Your Constitutional Rights
If law enforcement violated your constitutional rights during the traffic stop, arrest, or administration of the breathalyzer test, your attorney may be able to have the evidence suppressed. Protecting your constitutional rights is a fundamental part of the legal process, and any violation can jeopardize the prosecution’s case. Examples include:
Lack of probable cause for the stop
Failure to advise you of your Miranda rights
Unlawful search and seizure
Even if the breathalyzer results appear valid, if they were obtained through illegal means, they may be inadmissible in court. Suppression of this key evidence can greatly reduce the likelihood of a conviction. In some cases, it can lead to the dismissal of the charges altogether. It's crucial to thoroughly investigate the circumstances of your arrest to identify any possible violations.
What Happens If the Breathalyzer Results Are Thrown Out?
If the breathalyzer results are ruled inadmissible, the prosecution’s case may be significantly weakened. This often forces the prosecution to rely heavily on less concrete forms of evidence that can be more easily challenged. Without a BAC reading to rely on, they must use other evidence to prove intoxication, such as:
Officer observations (e.g., bloodshot eyes, slurred speech)
Field sobriety test results
Driving behavior (e.g., swerving, speeding)
A skilled attorney can argue that these observations are subjective and don't definitively prove impairment. In many cases, excluding breathalyzer results from evidence can lead to reduced charges or even a dismissal of the case, especially if the remaining evidence is weak or circumstantial.
Contact an Experienced Defense Attorney Today
If you've been charged with a DWI, don't assume that the breathalyzer results seal your fate. With the right legal strategy and an experienced criminal defense lawyer by your side, you may be able to get the evidence dismissed or the charges reduced. At Danford Law Firm, we represent clients in Kerrville, Texas, and the surrounding areas who are facing DWI charges. Contact us today to discuss your case.