Police often use field sobriety tests to determine if a driver is intoxicated by assessing their physical and mental capabilities. While performing these tests, police look for sensory clues such as your speech, odor, and demeanor to establish probable cause for a DWI arrest.

While a field sobriety test can lead to probable cause, the reliability of these tests is a subject of debate. According to the NHTSA’s Standardized Field Sobriety Testing Manual, the most accurate of the standardized tests has a maximum accuracy of 77% in detecting drivers with a blood alcohol concentration (BAC) at or above 0.10.

What three standard field sobriety tests does law enforcement use?

There are three primary standardized field sobriety tests endorsed by the NHTSA. These include:

• Horizontal gaze nystagmus (HGN) test: This test is deemed the most reliable field sobriety test. It involves following an object with one’s eyes. Police often consider involuntary eye movements as an indicator of intoxication.
• One-leg stand (OLS) test: When performing this test, you must stand on one leg and count to a specific number. Police will look for difficulty in maintaining balance and/or counting.
• Walk-and-turn (WAT) test: This involves walking heel-to-toe in a straight line, turning, and walking back. When administering this test, police often look for problems with balance or following instructions.

Does failing a field sobriety test lead to a DWI conviction?

Several variables influence the effectiveness and fairness of FSTs. In Texas, failing an FST doesn't necessarily guarantee a DWI conviction. At the most, it can lead to an arrest. After an arrest, further testing (e.g., breathalyzer or blood test) is conducted to measure BAC. The results of these tests are more definitive and carry significant weight in court. However, they can still be disputed.

An experienced Texas DWI defense attorney can challenge the validity of these tests. The most common challenges that arise during field sobriety tests include:

• Environmental and physical factors: Roadside conditions, such as uneven terrain, poor lighting, and extreme weather, often affect performance on field sobriety tests, especially if slipping and tripping hazards exist. Additionally, clothing and footwear choices (e.g., high heels or heavy boots) can hinder a person's ability to perform these tests.
• Health and medication factors: There are various health issues that can impact someone's ability to perform a field sobriety test. These include inner ear disorders, arthritis, and eye problems. Medications and age-related factors can also affect balance and mobility without necessarily impairing driving ability.
• Improper test administration: If an officer provides unclear instructions or demonstrates the tests improperly, it can lead to unfair failure. Even minor deviations in conducting the tests can significantly affect the outcomes.
• Anxiety and stress: The stress of being pulled over often triggers fight-or-flight responses. This makes it difficult to focus on tasks or control body movements.

Should I take a field sobriety test?

In Texas, you're not legally required to submit to a field sobriety test. You have the right to politely refuse to participate in one. Refusing such a test isn't an admission of guilt, and it can't be used against you in court. Plus, there are no penalties for refusing. However, you can still be arrested if an officer has other reasons to believe you're driving while intoxicated.

What are my legal options if I'm arrested for DWI in Texas?

If you refused a field sobriety test and were still arrested, don't just assume you're out of options. Amanda Webb - DWI Lawyer can investigate your arrest and look for evidence to help you fight the charges. With a law office in Conroe, we serve clients across Texas. Call us or contact us online to schedule your free DWI case evaluation.