How Los Angeles DUI Attorneys Defend Against Field Sobriety Test Results

Being pulled over under suspicion of driving under the influence can be a nerve-wracking experience. One moment you’re behind the wheel, and the next, you’re facing questions from law enforcement, roadside tests, and possibly a DUI charge. One of the most common tools officers use in DUI stops is the field sobriety test—a series of physical and cognitive exercises designed to evaluate a driver's impairment. But what many drivers don’t realize is that these tests are highly subjective and can be challenged with the help of an experienced Los Angeles DUI Attorney.

Field sobriety tests (FSTs) often serve as the initial piece of evidence in DUI cases. While law enforcement officers are trained to administer these tests according to standardized guidelines, several factors can affect the accuracy and fairness of the results. Weather conditions, physical limitations, nervousness, and even the footwear a person is wearing can all play a role in how someone performs. Yet, many people assume these tests are scientifically foolproof. The truth is far more complicated—and this is where the skills of a DUI defense lawyer become critical.

What Are Field Sobriety Tests?

There are three standard field sobriety tests approved by the National Highway Traffic Safety Administration (NHTSA): the Horizontal Gaze Nystagmus (HGN), the Walk-and-Turn, and the One-Leg Stand. Officers use these tests to look for clues that may suggest impairment. For example, in the Walk-and-Turn, an officer is looking for balance issues, whether the individual follows instructions accurately, or shows signs of stumbling or swaying.

These tests are inherently subjective. What one officer sees as a clue of intoxication might be dismissed by another. Additionally, the conditions under which these tests are administered can vary dramatically. Imagine trying to balance on one leg on a sloped shoulder at night while a flashlight is shining in your eyes and cars are speeding past. That scenario hardly mimics a controlled lab environment.

Challenging The Test Conditions

One of the primary strategies a Los Angeles DUI Attorney employs is questioning the environment and context in which the field sobriety tests were conducted. If the area was poorly lit, uneven, or noisy, those conditions could have significantly influenced the driver’s performance. Additionally, distractions like passing traffic, flashing lights, or even anxiety can cause a completely sober person to fail these tests.

Attorneys also investigate whether the officer followed the standardized procedures required when administering these tests. If any deviations from protocol occurred, the reliability of the test results can be called into question. For instance, the HGN test requires specific movements and timing to be valid. If the officer performed it incorrectly, the results should not be considered credible evidence of intoxication.

Medical and Physical Conditions Matter

Another powerful line of defense revolves around the physical or medical conditions of the driver. Many people have legitimate health issues—such as inner ear problems, old injuries, or neurological disorders—that can impair balance or coordination, even when they are completely sober. A good DUI attorney will work with medical professionals to provide documentation that explains how such conditions may have affected their client’s test performance.

Age and body type can also play a significant role. An older adult with limited mobility may not be able to walk heel-to-toe or stand on one leg for extended periods. Even being overweight can impact a person’s ability to perform balance-based exercises. These are not signs of intoxication—they’re human factors that should be taken into account when analyzing test results.

Psychological Pressure and Officer Bias

The psychological pressure of a traffic stop cannot be underestimated. Most people are not accustomed to being pulled over, let alone asked to perform physical tests in front of an armed officer with flashing lights all around. Anxiety, fear, and confusion can easily result in poor performance on field sobriety tests.

In some cases, officer bias may also influence the interpretation of test results. If an officer already believes a person is under the influence, they may unconsciously look for clues to confirm their suspicion. This confirmation bias can lead to exaggerating or misinterpreting signs of supposed impairment. A seasoned DUI attorney will analyze the body cam footage and police reports to identify any signs of bias or inconsistency in the officer’s observations.

Leveraging Expert Witnesses and Legal Precedent

Top-tier DUI defense attorneys often work with expert witnesses—individuals with specialized knowledge in toxicology, biomechanics, or police procedure—who can testify about the flaws and limitations of field sobriety tests. These experts can provide alternative explanations for a driver’s behavior and explain why a failed test does not necessarily indicate intoxication.

Legal precedent also plays a role. Courts have recognized the limitations of FSTs in various rulings, and an experienced attorney will know how to use those cases to support their argument. For example, if a similar case was dismissed because the field sobriety tests were conducted under unreasonable conditions, that ruling can be cited to argue for a similar outcome.

The Bigger Picture: Suppressing Evidence and Reducing Charges

If a DUI arrest is based heavily on field sobriety test results, and those results can be shown to be unreliable, a defense attorney can file a motion to suppress that evidence. If the motion is successful, the prosecution may lose a significant part of their case. This can lead to reduced charges, a plea bargain for a lesser offense, or even a complete dismissal.

In many cases, prosecutors are willing to negotiate when they realize the evidence is shaky. A capable Los Angeles DUI Attorney knows how to leverage these weaknesses to secure the best possible outcome for their clients, whether that means avoiding jail time, keeping a license, or preserving a clean criminal record.

The Importance of Immediate Legal Help:

Time is critical in DUI cases. Evidence needs to be reviewed, witnesses interviewed, and legal strategy developed quickly. The longer a person waits to get legal help, the more difficult it becomes to build a strong defense. With something as serious as a DUI charge, which can affect your job, insurance, and personal life, having a strong advocate from the start is essential.

Attorneys who focus on DUI defense, like those at Chesley Lawyers, bring the experience and dedication needed to navigate these complex cases. They understand the local court systems, know the common pitfalls in police procedures, and have the resources to mount a robust defense on your behalf.

Conclusion:

Field sobriety tests may seem like definitive proof in a DUI stop, but they are far from foolproof. They are flawed, subjective, and often misapplied. With the help of a skilled Los Angeles DUI Attorney, you can challenge the narrative, defend your rights, and fight for your future. Don’t let one roadside test change the course of your life—seek strong legal representation and take control of your defense.