Field Sobriety Tests Explained: A Beginner’s Guide

Field Sobriety Tests Explained: A Beginner’s Guide

Field Sobriety Tests (FSTs) are a series of physical and cognitive exercises conducted by law enforcement officers to determine whether a driver is impaired. These tests are often the first step in a Driving While Intoxicated (DWI) investigation, and understanding how they work can help you navigate the process if you’re ever stopped.

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What Are Field Sobriety Tests?

Field Sobriety Tests are designed to assess a driver’s coordination, balance, and ability to follow instructions—abilities that can be impaired by alcohol or drugs. While they can provide evidence of impairment, FSTs are subjective and not always accurate, which makes understanding them crucial for protecting your rights.

The Three Standardized Field Sobriety Tests

The National Highway Traffic Safety Administration (NHTSA) has approved three standardized tests for determining impairment:

1. Horizontal Gaze Nystagmus (HGN)

This test evaluates involuntary eye movements. The officer will ask you to follow a stimulus, such as a pen or flashlight, with your eyes while keeping your head still. Signs of impairment include:

• Inability to follow the stimulus smoothly.
• Jerking eye movements when looking to the side.
• Onset of jerking at less than a 45-degree angle.

2. Walk-and-Turn (WAT)

This divided-attention test assesses balance, coordination, and the ability to follow instructions. You’ll be asked to:

1. Take nine heel-to-toe steps along a straight line.
2. Turn around on one foot.
3. Take nine heel-to-toe steps back.

Indicators of impairment include:

• Can’t balance during instructions
• Starting too soon
• Stops while walking
• Misses heel to toe (even though the test allows for 1/2 an inch of leeway)
• Stepping off the line
• Uses arms for balance
• Turns improperly
• Wrong number of steps

3. One-Leg Stand (OLS)

In this test, you must stand on one leg while raising the other foot about six inches off the ground. The officer will time the test for 30 seconds. Signs of impairment include:

• Putting the raised foot down prematurely
• Uses arms for balance
• Sways while balancing (but how much swaying makes this a clue?—no one knows!)
• Hopping

Are Field Sobriety Tests Reliable?

While these tests are widely used, they are not foolproof. Factors that can affect test results include:

• Medical Conditions: Inner ear problems, neurological disorders, or injuries can mimic signs of impairment.
• Environmental Factors: Uneven surfaces, poor lighting, or bad weather can make the tests more challenging.
• Nervousness or Fatigue: Anxiety or exhaustion can impair performance, even if you’re sober.
• The “studies” that made the FSTs standardized were never peer reviewed. In this author’s opinion, there is only one reason why—because something is wrong with the study that it can’t hold up to peer-review scrutiny.

Learn more about the limitations of these tests in Common DWI Myths Debunked.

Can You Refuse Field Sobriety Tests?

In Texas, you have the right to refuse field sobriety tests. However, refusal can raise suspicions and may lead to further investigation or arrest. If you’re stopped, it’s crucial to remain polite and know your rights. Generally, if the officer asks you to get out of the car for a DWI investigation, the decision has already been made to arrest. These tests are hard to do even when sober, as people do not normally engage in these roadside theatrics. Officers practice hundreds of times whereas most people don’t practice these FSTs at all. If you have been taking any substance that could impair your mental or physical faculties, you have the choice to politely refuse to do the FSTs. If you know you have vertigo or bad balance, be sure to tell the officer that on scene. You are usually being recorded and this information can be used by a skilled defense attorney to aid in your defense.

For a deeper understanding of your rights during a DWI stop, read Implied Consent Laws: What They Mean for You.

What Happens After Field Sobriety Tests?

If an officer determines that you’re impaired based on the results of the FSTs, you may be arrested and subjected to a chemical test, such as a breathalyzer or blood test, to confirm your Blood Alcohol Concentration (BAC). For more on this process, visit Blood Alcohol Concentration (BAC): How It’s Measured.

How a Criminal Defense Attorney Can Help

Field sobriety tests are subjective and prone to error, but an experienced criminal defense attorney near you can:

• Challenge the validity of the test results.
• Investigate whether the officer followed proper procedures.
• Use environmental or medical factors to dispute the charges.

At David Smith Law Firm, PLLC, we have experience defending clients against DWI charges, leveraging our criminal law expertise to protect your rights and achieve the best possible outcome.

Field Sobriety Tests Explained: DWI Basics for BeginnersConclusion

Field Sobriety Tests play a significant role in DWI investigations, but they are not always accurate or fair. Knowing what to expect and understanding your rights can make all the difference if you’re stopped by law enforcement.

If you’ve been charged with a DWI, don’t navigate the legal system alone. Contact David Smith Law Firm, PLLCtoday for expert guidance and representation.