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Charged with DWI?
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San Antonio Field Sobriety Test Attorneys

Challenging the Validity of Field Sobriety Tests

DWI arrests are often based on field sobriety tests. Police officers who suspect impaired drivers often use these tests to determine probable cause of intoxication and to establish the grounds for an arrest. The officer administering the test will usually provide testimony regarding the testing that can additionally be used in court to assist the prosecutor’s contention that the driver was driving while impaired.

If you have taken a field sobriety test that ended in a “failure” to pass, it does not provide solid evidence that can or should lead to a conviction. At Smith & Vinson Law Firm, we deal with these tests on a regular basis. We do not take them at face value. Our San Antonio DWI lawyers can and will exhaustively investigate and assess your particular case to get to the truth. After doing so, we can determine how best to defend you in court by challenging such tests and other evidence that may be used against you. Throughout the duration of your DWI case, we will fight relentlessly for your constitutional rights.

Call Smith & Vinson Law Firm for a free case evaluation at (210) 960-9557 today.

What Are Field Sobriety Tests?

San Antonio law enforcement generally use three standardized field sobriety tests when pulling drivers over for suspected DWI. These tests seek to uncover both physical and mental impairment caused by drugs or alcohol.

These tests include:

  • Walking and turning
  • Standing on one leg
  • Horizontal gaze nystagmus (checking for involuntary eye jerking when looking to the side)

How We Challenge Field Sobriety Tests

These tests examine one’s coordination, balance, and ability to follow directions. Standards have been set on which police officers determine results. These tests are not always reliable, however, and they can be further skewed by improper administration. That is why our San Antonio DWI attorneys believe that it is vital to challenge their results whenever possible.

We may challenge field sobriety tests by questioning:

  • How the testing area was lit
  • Whether the ground was flat, pitted, or otherwise uneven
  • What type of shoes the driver wore
  • How the instructions were relayed to the driver
  • Whether or not the officer properly evaluated what he saw
  • Whether or not the driver had a physical condition that would affect his ability to perform the tests
  • Whether or not the officer received proper training on how to administer such tests

Learn more about how Smith & Vinson Law Firm can challenge your DWI case. Contact us at (210) 960-9557 today.

Our Clients Are Our Biggest Endorsers
Hear What They Have to Say

  • 110% glad I chose Jarrod to represent and fight for me.

    “Pay them, be honest with them and communicate with them and they will fix your mistake. Plain and simple. Charged 1st DWI offense. Called in. Told them scenario. Worked with payment methods (very important) .I had numerous lawyers to choose from. 110% glad I chose Jarrod to represent and fight for me. Throughout whole process I had the utmost confidence in Mr. Smith and his work. the goal when we first met was to "get the DWI dismissed" and that is exactly what happened. mission accomplished. if you need a DWI removed call jarrod”

    Ronald D.

  • Outstanding Lawyer

    “He is well versed in evidence and criminal law nuances, skills which allow him to level the playing field for his clients and make certain they get a fair chance at justice.”


  • Awesome communication

    “They handle my case incredibly well and warned me on the possible negative outcomes, overall completely satisfied me through the whole process. ”

    Elmer Marqueiz

  • He's a real lawyer!

    “A civil issue arose in Austin with a family member. We sought the advice of a well named Austin attorney. This unnamed attorney provided egregious legal advice. In court, a lifetime civil injunction was ruled by the judge on this non-criminal civil issue. Once learning of this judgement we immediately started looking for another attorney and found Brad Vinson, with Smith and Vinson. Simply put, Brad had this entire debacle reversed and a new judgement set for what is customarily ruled in similar cases. It didn't take long either. I only wish we had called Brad first. He's a real lawyer!”


  • Exceptionally versed in the intricacies of Texas criminal law

    “Having never been exposed to the criminal system, hiring an attorney was daunting task. Attorney Brad Vinson was informative, professional yet sympathetic with his approach to my case. Mr. Vinson was open to opinion and ensured that all legal avenues were considered and addressed before presenting a course of action. Ultiamtely, Mr. Vinson was able to negotiate a reasonable settlement dispite many hoops and hurdles presented by the prosecuting county. I would highly recommend Smith and Vinson for representation in a criminal matter.”


  • Top Attorney Avvo Rating 10.0
  • Texas Criminal Defense Lawyers Association
  • Avvo 10.0 Rating
  • Texas Bar College
  • DUI Defense Lawyers Association
  • National College for DUI Defense
  • Avvo 5 Star Reviews
  • Avvo Clients' Choice Award


  • We are accessible to you. Our attorneys can be reached 24/7.
  • Bold and fearless defense are what we are known for.
  • Turn to us for straightforward legal advice when you need it.
  • We offer free consultations to every single client served.