# How DWI Field Sobriety Tests Work | TadLaw **Table of Contents***[*Expand*]* 1. Sobriety Tests & The Law 2. The Standardized Field Sobriety Test (SFST) Suite 3. Non-Standardized Tests 4. Factors Affecting Sobriety Tests 5. Video Evidence 6. Challenges and Defenses 7. Accused of Drunk Driving in Houston? When drivers are pulled over under suspicion of driving while intoxicated (DWI), officers often administer field sobriety tests. These tests are designed to assess a driver’s physical and cognitive faculties to determine if they’re under the influence of alcohol or drugs. If the police officer determines that the driver is intoxicated, they’ll be arrested and get free night’s stay at the Harris County jail. If you’re ever stopped on suspicion of drunk driving in Greater Houston, we don’t recommend partaking in any of these tests. **If you need to talk with a defense attorney following an arrest for drunk driving, contact our office to schedule your 100% free & confidential consultation with our DWI lawyers.** **Call us 24/7 at [281-280-0100](tel:2815022122).** ## Sobriety Tests & The Law Under the Texas Transportation Code, Section 724.011, a person arrested for a DWI is deemed to have consented to take a sobriety test. This is often referred to as “implied consent.” Failure to comply can lead to automatic license suspension. The administration of these tests and the interpretation of results are standardized by the National Highway Traffic Safety Administration (NHTSA). ## The Standardized Field Sobriety Test (SFST) Suite The NHTSA endorses three standardized tests to form the SFST suite, which are widely utilized by law enforcement agencies in Greater Houston and throughout Texas: ### 1. Horizontal Gaze Nystagmus (HGN) ![Art Concept - Field Sobriety Test on Houston DWI Suspect](https://tadlaw.com/wp-content/uploads/2024/04/Field-Sobriety-Test-Art-Concept-300x200.jpg) DRAMATIZATION This test involves an officer observing the eyes of a suspect as they follow a slowly moving object like a pen horizontally. Officers are trained to look for signs of nystagmus—a jerking of the eye that occurs as the eye gazes to the side. This involuntary jerking can intensify with impairment. ### 2. Walk-and-Turn In this test, the suspect is instructed to take nine steps, heel-to-toe, along a straight line, then turn on one foot and return in the same manner. This test evaluates the suspect’s ability to perform tasks requiring divided attention, which mimics the skills necessary for driving. ### 3. One-Leg Stand The one-leg stand test requires the suspect to stand with one foot approximately six inches off the ground and count aloud until told to put the foot down. This test measures balance, coordination, and the ability to follow directions. For a free legal consultation, call [(281) 280-0100](tel:+12812800100) today ## Non-Standardized Tests Aside from the SFSTs, officers might use additional tests like asking a suspect to recite the alphabet or count backward. These are not standardized under NHTSA guidelines and are more subjective in nature. ## Factors Affecting Sobriety Tests Several factors can influence the accuracy of field sobriety tests. Physical conditions, nervousness, weather, and road conditions can all impact your performance of these tests. ## Video Evidence These days, most field sobriety tests are recorded on video. Video evidence can be powerful in court. Such evidence can provide a factual basis to challenge the subjective conclusions of officers about a suspect’s performance. ## Challenges and Defenses Attorneys Tad Nelson & Amber Spurlock are highly experienced DWI lawyers. We know the results of field sobriety tests can be contested. Some of our most successful tactics for challenging this kind of evidence focuses on the proper administration of these tests. We might also challenge the interpretation of the test results. Sometimes, external factors can also invalidate the results. [Click to contact](https://tadlaw.com/contact-us/) our dwi lawyer today ## Accused of Drunk Driving in Houston? ### Call DWI Lawyers Tad Nelson & Amber Spurlock Today! ![Attorney Tad Nelson, Board Certified in Criminal Law by the Texas Board of Legal Specialization](https://tadlaw.com/wp-content/uploads/2023/07/Attorney-Tad-Nelson-Board-Certified-in-Criminal-Law.webp) A conviction for DWI can create all kinds of complications in your life ranging from higher car insurance rates, professional limitations, not to mention a criminal record. Having a skilled defense attorney on your side gives you the best chance for the best outcome. Attorneys Tad Nelson and Amber Spurlock are known for leveraging their deep expertise as ACS/CHAL Lawyer-Scientists to provide a robust defense our clients. We know that **the science** behind field sobriety tests can prove invaluable in challenging questionable results. **If you or someone you know needs assistance, don’t hesitate to contact Houston DWI lawyers Tad Nelson & Amber Spurlock at [281-280-0100](tel:2815022122) for a confidential consultation.** **Resources** - Should I Avoid a Breathalyzer Test? - What Happens if I Refuse a Breathalyzer During a DWI Stop? - Pro & Cons of Texas Field Sobriety Tests - What Happens if I Fail My Breathalyzer Test? 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