Top Strategies DUI Defense Attorneys Use to Challenge Breathalyzer and Field Sobriety Tests

Facing a DUI charge can be an incredibly daunting experience, carrying with it severe penalties including fines, license suspension, increased insurance rates, and even jail time. Often, the prosecution's case heavily relies on the results of Breathalyzer tests and Field Sobriety Tests (FSTs) administered by law enforcement at the scene. While these tests are designed to provide evidence of impairment, they are far from infallible. A skilled DUI defense attorney understands the nuances and potential flaws in these tests, employing various strategies to challenge their accuracy and administration.

At Law Offices Of SRIS, P.C., we know that a thorough and aggressive defense can make all the difference. Challenging the evidence gathered from Breathalyzer and FSTs is a cornerstone of effective DUI defense. Let's delve into the key strategies attorneys use to scrutinize these crucial pieces of evidence.

Challenging Field Sobriety Tests (FSTs)

Field Sobriety Tests are a series of evaluations officers use to assess a driver's physical and mental impairment. The three standardized FSTs are the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn test, and the One-Leg Stand test. While widely used, their scientific validity and administration are frequently open to challenge.

1. Improper Administration by the Officer

One of the most common defense strategies involves questioning whether the officer administered the FSTs correctly. The National Highway Traffic Safety Administration (NHTSA) sets forth strict guidelines for how these tests should be performed. Any deviation from these protocols – such as failing to provide clear instructions, conducting the tests on uneven terrain, or in poor lighting conditions – can compromise the validity of the results. An experienced DUI defense attorney will meticulously review dashcam or bodycam footage to identify any procedural errors made by the officer.

2. Subjective Interpretation and Non-Impairment Factors

FSTs rely heavily on the subjective interpretation of the officer. What one officer perceives as a "clue" of impairment, another might view differently. Furthermore, many factors unrelated to alcohol impairment can mimic the signs of intoxication during an FST. Fatigue, nervousness, medical conditions (such as inner ear problems, leg injuries, or neurological disorders), poor balance, age, or even inappropriate footwear can all lead to a poor performance, wrongly suggesting impairment.

3. Lack of Medical or Physical Ability

Defense attorneys often argue that a driver's poor performance on FSTs was due to a pre-existing medical condition, injury, or physical limitation, rather than intoxication. For instance, an individual with a back injury might struggle with the Walk-and-Turn test, or someone with knee problems might find the One-Leg Stand test impossible, regardless of their sobriety. An attorney can present medical records or expert testimony to support such claims, demonstrating that the FST results are unreliable indicators of impairment for that specific individual.

Challenging Breathalyzer Tests

Breathalyzer tests are designed to measure a person's Blood Alcohol Content (BAC) by analyzing the alcohol content in their breath. While often presented as definitive evidence, these devices are not foolproof and can produce inaccurate readings due to various factors.

1. Calibration and Maintenance Issues

Just like any sophisticated piece of equipment, Breathalyzer devices require regular calibration and maintenance to ensure accuracy. If a device has not been properly calibrated, serviced, or inspected according to manufacturer specifications and state regulations, its readings can be highly unreliable. A skilled DUI Defense Attorney will demand access to the device's maintenance logs and calibration records to check for any lapses that could invalidate the test results.

2. Operator Error and Procedural Violations

Even a perfectly calibrated machine can produce inaccurate results if not operated correctly. Law enforcement officers are required to follow specific protocols when administering a Breathalyzer test. This includes observing the suspect for a minimum of 15-20 minutes prior to the test to ensure they haven't ingested anything, vomited, or regurgitated, which could introduce "mouth alcohol" and artificially inflate the reading. Failure to provide clear instructions for taking the breath sample (e.g., proper breathing technique) can also lead to erroneous results. Any such procedural errors can be grounds for challenging the test's admissibility.

3. Medical Conditions and External Factors

A range of physiological conditions and external factors can interfere with Breathalyzer accuracy. Individuals suffering from GERD, acid reflux, or other conditions that cause stomach contents to come up into the mouth can have mouth alcohol present, leading to falsely high BAC readings. Diabetics in a state of ketoacidosis can produce acetone in their breath, which some older Breathalyzer machines can misinterpret as alcohol. Even certain dental work, mouthwashes, or medications can potentially impact the results. A thorough defense investigates these possibilities to demonstrate why the Breathalyzer reading might not reflect actual impairment.

4. Rising BAC Defense

The "rising BAC" defense is a critical strategy employed by DUI defense attorneys. Alcohol takes time to be absorbed into the bloodstream. This means a person's BAC at the time of the Breathalyzer test (which might be an hour or more after the stop) could be significantly higher than their BAC at the time they were actually driving. If the attorney can demonstrate that the defendant's BAC was below the legal limit when they were operating the vehicle, even if it rose above the limit later, it can lead to an acquittal or reduced charges.

Navigating a DUI charge requires a deep understanding of the law, scientific principles, and police procedures. The strategies outlined above are just a few examples of how a knowledgeable DUI defense attorney can challenge the evidence presented by the prosecution regarding Breathalyzer and Field Sobriety Tests. If you or someone you know is facing DUI charges, it is crucial to seek immediate legal counsel. Contact Law Offices Of SRIS, P.C., to ensure your rights are protected and to explore every possible defense strategy available to you.