

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 administering officer will usually testify to how you performed on the test in court. This can assist the prosecutor's contention that you were driving while impaired.
Failing a field sobriety test is not solid evidence of intoxication. On its own, a field sobriety test should not 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)
Common Mistakes During Field Sobriety Tests
When facing a field sobriety test, individuals often make critical mistakes that can negatively impact their case. Understanding these common errors can help you prepare and respond appropriately if you ever find yourself in this situation.
- Failing to Follow Instructions: One of the most frequent mistakes is not fully understanding or following the officer's directions. It's crucial to listen carefully and follow the specific steps provided during the test, as failure to do so can lead to an automatic "failure" designation.
- Nervousness and Anxiety: The pressure of the situation can make anyone anxious, which may result in shaky movements or difficulty concentrating. These symptoms can be mistaken for impairment, so it’s important to remain as calm as possible during the test.
- Inappropriate Footwear: Wearing unsuitable shoes, such as flip-flops or high heels, can hinder balance and coordination during the tests. If you are pulled over, try not to wear unstable shoes that could compromise your support and grip.
- Inadequate Warm-Up: Many individuals don't consider the physical demands of certain tests. A brief warm-up before performing tasks like standing on one leg or walking heel-to-toe can help improve balance and coordination.
- Ignoring Health Conditions: If you have a legitimate medical condition that affects your physical stability, it is crucial to inform the officer before taking the test. Failing to disclose such information could result in misleading results that may be used against you.
By being aware of these common pitfalls, you can take steps to mitigate their effects if faced with a field sobriety test. Remember, even if you believe you have failed a field sobriety test, it does not automatically mean you will be convicted of DWI. Contesting the results with experienced legal representation can make a significant difference in your case.
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.

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Throughout the 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.- Ronald D.

A Proven Track Record
Check Out Our Recent Case Results
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Dismissed Assault Family Violence
During a dispute with her boyfriend, our client threw a brass statue against a wall, which ended up bouncing and hitting him. He called the police and our client was arrested for Assault Family Violence.
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Dismissed DWI
Our client was stopped by a police officer for driving the wrong way down a one-way street. A Blood Warrant was issued, and the test came back .09. Our client was new to the area and attempting to get a job. Pleading guilty to a DWI was not an option. After negotiating with the prosecutor, our firm was able to get the DWI charge dismissed after successful completion of 18 months deferred prosecution.
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Felony Rejected Pre-Indictment Aggravated Assault with a Deadly Weapon and Interference with a 911 Call
Our client’s girlfriend’s car was being repossessed. Our client had belongings in the car, including his work equipment and his firearm. Our client attempted to get his belongings out of the car before it was being towed away. The tow driver accused our client of threatening him with the gun our client was retrieving while he was on 911 with the police.
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Cases Dismissed Aggravated Assault with a Deadly Weapon and Misdemeanor Assault with Bodily Injury
Our client was accused of attacking another man on two separate occasions, once with his hands and once with a knife in our client’s home. Our client had told the man to stay away from his family because the man had made romantic advances toward his wife, but the man persisted.
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Case Dismissed Aggravated Robbery
Our client was accused of robbing another person at gunpoint for some sneakers along with a co-defendant and getaway driver. We investigated the evidence and discovered that it was the co-defendant who arranged for the purchase of the sneakers, and that surveillance video disproved the State’s theory that a gun was brandished or that our client knew what was going on.