A standardized field sobriety test (SFST) are three tests one is asked to perform by law enforcement agents during a traffic stop, so the officer can determine if alcohol or drugs have impaired the driver of the vehicle. These tests were created in the 1970s and have been deemed scientifically validated and therefore, admissible in court as evidence in almost all states.

Summary of Field Sobriety Tests According to the National Highway Traffic Safety Administration

Research has shown that when police officers are appropriately trained to conduct field sobriety tests; they can identify alcohol-impaired drivers, more than 90% of the time. There are three tests that make up the field sobriety testing, which if a driver fails, the officer is then able to arrest them with probable cause for DWI. The three tests include:

  • HGN (horizontal gaze nystagmus) test is an involuntary jerk of the eyeball when you gaze to the side. Typically nystagmus happens when you rotate your eyes at high peripheral angles. When the effects of alcohol impair a person, nystagmus will be exaggerated and can happen at lesser angles. Alcohol will also impair how smoothly a person can track a moving object.

    As an officer performs the horizontal gaze nystagmus test, they will watch the eyes of a suspected drunk driver as they follow a slowly moving object such as a small flashlight or pen. There are three signs the officer will look for when conducting this test; if the suspected drunk driver cannot follow a moving object smoothly, if their eyes jerk distinctly, and if there is sustained nystagmus when their eyes are at maximum deviation.

    If the suspect’s eyes indicate nystagmus prior to the 45 degrees of center, it is highly likely they will have a BAC of .08 or more. A study showed that this test provides accurate results in more than 85% of the subjects, but it is not a foolproof method of testing. The HGN test can also be a sign of the suspect consuming other legal substances such as seizure medications or depressants.

  • The walk-and-turn test is another part of the field sobriety tests and is used to have the suspected drunk driver walk in a straight line. The officer will ask the driver to take nine steps by touching their heels to their toes along a straight line. After making the nine steps, they are then asked to turn around on one foot and return using the same method of walking by placing one heel in front of the other toe.

    There are eight indicators the officer will look for to determine if the suspect is under the influence of alcohol:

    • They are not able to maintain their balance as the officer gives the instructions
    • The suspect begins before the instructions are fully given
    • The suspect has to stop and regain their balance before fully completing the required steps
    • The driver is not able to walk by touching their heels to their toes
    • The suspect has to use their arms to maintain their balance
    • They are not able to stay in a straight line
    • They do not complete the turn correctly
    • They do not walk the correct number of steps


    Studies conducted on the accuracy of this testing method showed it has accurate results, more than 75% of the time. Persons who exhibit two or more indicators during the performance of this test will have a BAC of .08 or more.

  • One-Leg Stand test is performed by the officer asking the suspected drunk driver to stand with one of their feet about six inches off the ground. While standing in this position, they are asked to count by one thousand- one thousand one, one thousand two, and so on until the officer tells them to stop and put the foot back down.

    The counting should be done for thirty seconds while the officer looks for four indicators of impairment:

    • The driver sways as they attempt to balance
    • The suspect needs their arms to maintain balance
    • The suspect cannot maintain balance without hopping
    • The driver cannot keep their foot in the air and continually puts it back down


    A study was conducted to determine the validity of this testing and found it is more than 80% accurate in determining if an individual is impaired by alcohol. When a driver exhibits two or more of the indicators, it is extremely likely they will have a BAC of .08 or more.

Texas Field Sobriety Testing

Texas uses the field sobriety testing as a means to determine if a suspect is DWI. Officers will ask questions before administering the test to confirm their suspicions a driver is intoxicated such as whether or not you have been drinking, where are you driving from and a few others to get a feel for your mental and physical condition. You are not required to answer these questions; however, the officer may give you the impression you have to answer.

If you fail the field sobriety testing, the officer can then ask you for a sample of your blood or breath as they read the DIC-24 form.

  • DIC-24 Statutory Warning- When a Texas law enforcement officer arrests a driver for DWI, they are required to read the DIC-24 Statutory Warning. Many people do not understand what this warning entails as it can be confusing and misleading, especially at the time the arrest occurs.

The warning is a redundant method of explaining to you what will happen if you submit or refuse to provide a sample for the BAC test. It explains the risks to your license if you choose to submit or decline a sample for the test. There are a variety of scenarios possible depending on your case and if you have prior DWI arrests on your criminal record.

If you are being arrested for the first time for DWI and you refuse the BAC test, your license privileges can be suspended for 180 days. If you do submit the sample on your first arrest, you are then at risk for a 90-day suspension. When reading this warning to suspects, it is made to sound as though your best choice is to take the test. This confusing statement is the reason; it is vital for people to understand their rights.

If you are arrested, whether or not you have submitted a sample, you will be given what is called the DIC-25 paperwork. This paperwork is a temporary driving permit and advises you of your right to request an ALR Hearing within 15 days to lift the suspension of your driving privileges.

  • An ALR Hearing is the civil, administrative process. It is unrelated to criminal court proceedings and applies to individuals arrested for DWI who have not submitted, or who have failed the breath or blood test.

    If you have refused to give a sample for a BAC test or have failed the test, you may lose your driver's license to suspension anywhere from 90 days to 2 years. You will have 15 days from the arrest date to request an ALR Hearing to contest the suspension.

    At your hearing, a judge will listen to the evidence and issue a final, appealable decision on whether or not they will lift the suspension.

When you have a choice and are willing to provide a sample, take the Breathalyzer. Studies have shown that a jury has a harder time believing the results of the Intoxilyzer/Breathalyzer, and you then do not have to go through a painful blood draw. Another benefit to taking the test is if you are sober, and the test proves this to the officer, you will more than likely be able to go on your way.

Non-Standard Texas Field Sobriety Tests

A Texas law enforcement officer may request one of the above standardized field sobriety tests, or they may ask you to perform a non-standardized test. Some of the non-standardized tests include:

  • Tipping your head backward as your feet remain positioned together
  • Counting the fingers on an officer’s hand
  • Touching your finger to your nose as you close your eyes
  • Repeating the alphabet backward
  • Leaning backward as you stretch your arms outward

These tests sound ridiculous because they are, and the officer who asks you to perform them is likely looking for a reason to make an arrest. You are not required to perform these tests and can request to have your defense attorney present before doing any testing or answering any questions.

Can You Refuse the Texas Field Sobriety Tests?

The officers may make you feel as if there is no choice for you other than performing the field sobriety tests. The fact is that you have the right to refuse any field sobriety test, but whether or not it is a good idea to refuse is another question. Refusal of the tests can become a complicated issue.

If you know you are sober and have not taken any drugs, your acceptance of taking the tests could save you a lot of time and hassle. If you have consumed alcohol or are under the influence of illegal substances, it may be best to refuse the tests and ask to speak to your attorney.

There are pros and cons to refusing to take the field sobriety test when asked at the time of a traffic stop. The benefit to refusing is that the prosecution will not be given any misleading footage that could be used against you in court. They will have to base their evidence on the potentially unreliable breath or blood analysis to prove you were intoxicated. The disadvantage of refusing the test is you will more than likely be arrested on suspicion of the officer that you are DWI.

Your best option is to request your attorney be present for all testing. The field sobriety tests are designed for most people to fail, and having legal representation will allow your tests to be conducted more fairly. The police would like you to believe the field sobriety test is a foolproof method of proving whether or not you are DWI, but there is a growing body of proof that suggests otherwise.

Factors to be Considered in Field Sobriety Tests

There are many factors that can affect one’s blood alcohol content:

  • The rate they consume alcohol
  • A person’s age
  • A person’s gender
  • The body type of an individual
  • A person’s muscle/fat ratio
  • The type of medication a person may be taking
  • How much a person has eaten during the day
  • Whether or not the person is a diabetic or not

No two people are the same, and with the number of factors that have to be taken into account regarding the amount of alcohol that shows up in their system makes the testing full of loopholes. The field sobriety testing is also not foolproof, as no two individuals will perform this test identically. These tests cannot gauge an individual's alcohol content reliably.

Defense Against Field Sobriety Test Results

Texas law enforcement officials use the field sobriety testing method to establish probable cause of DWI even though there is evidence these tests are flawed and do not prove an individual is intoxicated. The prosecution will need positive blood or breath test results showing you were .08 BAC or more to receive a DWI conviction in your case. If you fail the field sobriety test, it consolidates their case against you; however, these results can be argued. Having a strong legal defense attorney working with you on these charges can help you prove the field sobriety test results in your case are not reliable.

Driving can often be a stressful event. You have to watch the road signs, other drivers, traffic can be heavy and slow you down from reaching a destination on time, or many other factors that can occur to increase your stress levels. When you are pulled over, this only worsens your experience. A police officer can pull you over for any number of reasons, including suspecting you are DWI.

There are several driving tactics that you may display, such as hesitating at a stoplight or stopping too quickly, swerving, or any number of questionable driving methods that catch the attention of the police. When you are stopped for questionable driving tactics, the police can ask you to perform one of the many field sobriety tests they use to determine if a driver is intoxicated.

It is well known that if you fail your field sobriety test, the police can then arrest you for DWI. Prosecutors will then use the results of those tests as the fact that you were over the legal limit to be driving at the time of the arrest. If you refuse to take the tests, the prosecution will often go with the fact that you would not consent to them, because you knew you would fail due to alcohol consumption.

An experienced defense attorney can argue the case that almost everyone is unlikely to pass the field sobriety tests whether they are drunk or not. The tests are biased, and a failed sobriety test can be defended in the courtroom when you have a knowledgeable DWI Defense Lawyer working by your side.

One of the tests performed as a field sobriety test is the HGN (horizontal gaze nystagmus). There are studies on this test that show only five out of a hundred cases police officers correctly administer this test. The reason for this small number is that law enforcement is not precisely taught how to apply the testing. There is also the chance of an officer being taught correctly; however, they often become lazy and don’t follow all the protocols necessary to achieve accurate results.

The HGN test can be failed for several medical, environmental, and biological reasons. A failed HGN test can have nothing to do with the amount of alcohol consumed. The police will not take any of these factors into consideration when applying the test, their only concern, and those of the prosecution is that you failed. Your attorney can argue your test results were based on a mental or physical condition you suffer or any number of factors that were present at the time of the testing that impacted your results.

Another field sobriety test you can be asked to perform is the walk-and-turn. If you do not complete this test to the satisfaction of the officer, you can be arrested for DWI. You only have to make two errors out of the eight steps in this test for them to consider you under the influence. One indicator they look for is whether or not your heel and toe are within a half inch of each other. Being on the side of the road makes for stressful conditions for anyone to properly perform a test, and with small rocks and broken glass around you, this is a difficult step to maintain.

The walk-and-turn test is challenging for anyone to perform correctly. You are standing by an officer of the law who is probably not addressing you in the friendliest of terms, there is constant traffic speeding past you, and you might even have light being shined in your eyes all the while having to listen to directions on how to walk and turn. It is difficult to determine what your performance will be based on by the police officer administering the test. They do not know how you would perform the test when perfectly sober, so how can they tell you failed, and what the reason is for failing? A defense attorney can argue the results of the walk-and-turn test results based on these questionable factors.

The third of the most commonly used field sobriety tests is the one-legged stand. This thirty-second test is easy to fail by anyone under any condition. By missing one of the four clues the officer is looking at as a fail for the test, you can be arrested for DWI. The officer does not have to advise you what they are looking for in the test; for example, they can tell you if you put your foot down, you should pick it back up. What they fail to say is that by putting your foot down, you are indicating intoxication.

If you are told this statement during your test, your defense attorney can argue the announcement is encouraging one to put their foot down, or at least it is acceptable to put the foot down. Making a statement such as this to a suspect encourages them to score a point against themselves.

Defense Against Breath and Blood Testing Evidence

Additional field sobriety tests you can be asked to perform when pulled over on suspicion of DWI are the breath and blood test. Keep in mind there are national protocols in place as to the scientific evidence for breath and blood tests; however, the police have much lower standards than the national ones. A good breath testing machine should have filters in place to keep other chemicals from being read during the process. These machines have to be able to test for acetone because this can skew your BAC reading.

The machine will not give a correct reading if you have diabetes or are on a high protein with a low carbohydrate diet with acetone in your blood or breath. If the machine does not correctly identify the acetone, it will appear as if you have alcohol in your system. Your defense attorney will be able to see this type of reading and argue on your behalf that the test results cannot be used as evidence. This information may have your case dismissed if there is no other compelling evidence showing you were DWI.

The machines used for these tests are required to be calibrated regularly and in good repair to function correctly. Proving the police department is not following these procedures can also have test results thrown out, leaving the prosecution with little to no evidence to continue with your case.

Find a Fort Worth DWI Attorney Near Me

If you feel the police have wrongly accused you of DWI based on field sobriety tests, call the Fort Worth DWI Defense Lawyer at 817-470-2128. We understand the complexities of these tests and how results can be skewed to implicate you for DWI wrongly. When you call, we can set up a time to meet and create a defense strategy to begin fighting your charges and protecting your good name.