Driving while intoxicated (DWI) is a serious offense in Texas, and law enforcement officials take it very seriously. If you are pulled over and suspected of driving under the influence, you may be asked to perform a field sobriety test to determine whether you are impaired. In this blog post, we will provide an overview of DWI field sobriety tests in Texas.

What are DWI Field Sobriety Tests?

DWI field sobriety tests are a series of physical and cognitive tests that law enforcement officials use to determine whether a driver is impaired. There are three standardized field sobriety tests (SFSTs) that have been developed by the National Highway Traffic Safety Administration (NHTSA) and are used in Texas:

Horizontal Gaze Nystagmus (HGN) Test

The HGN test is a physical test that involves the officer observing the driver’s eyes as they follow a small object, such as a pen or flashlight, as it moves back and forth horizontally in front of them. The officer is looking for an involuntary jerking movement of the eye known as nystagmus. Nystagmus is a rapid, rhythmic movement of the eyes that can be caused by alcohol or drug impairment.

How Does the HGN Test Work?

The HGN test works by measuring the involuntary jerking movement of the eye, which can be an indicator of alcohol or drug impairment. The officer will move the object horizontally across the driver’s field of vision while observing the driver’s eyes. The officer will be looking for three specific indicators of impairment:

  • Lack of Smooth Pursuit – If the driver’s eyes cannot follow the object smoothly, and instead make small jerking movements, it can indicate impairment.
  • Distinct Nystagmus at Maximum Deviation – If the driver’s eyes jerk when they are looking as far to the side as possible, it can indicate impairment.
  • Onset of Nystagmus Prior to 45 Degrees – If the driver’s eyes begin jerking before they reach a 45-degree angle, it can indicate impairment.

Each of these three indicators is given a score, and if the driver scores four or more out of six, it may indicate impairment.

Limitations of the HGN Test

While the HGN test is one of the most reliable field sobriety tests, it is not perfect. There are several limitations to the HGN test that can impact its accuracy, including:

  • Medical Conditions – Certain medical conditions, such as neurological disorders or eye diseases, can cause nystagmus and lead to a false positive.
  • Environmental Factors – The HGN test may be impacted by environmental factors, such as bright lights or flashing lights, that can cause nystagmus.
  • Officer Error – The HGN test requires a properly trained officer to administer it, and errors in administration can lead to inaccurate results.

Walk and Turn Test

The Walk and Turn test is a physical test that requires the driver to take nine heel-to-toe steps along a straight line, turn around, and take nine heel-to-toe steps back. The officer is looking for specific indicators of impairment, such as a lack of balance or the inability to follow instructions.

How Does the Walk and Turn Test Work?

The Walk and Turn test works by measuring a driver’s ability to perform a divided attention task. The driver must listen to the officer’s instructions, maintain their balance while walking along the line, turn around, and walk back along the line. The officer is looking for specific indicators of impairment, including:

  • Inability to maintain balance while listening to the officer’s instructions.
  • Starting before the officer gives the signal to begin.
  • Stopping while walking along the line.
  • Failing to touch heel-to-toe while walking.
  • Stepping off the line while walking.
  • Using arms for balance.
  • Making an improper turn.
  • Taking an incorrect number of steps.

If the driver exhibits two or more of these indicators, it may indicate impairment.

Limitations of the Walk and Turn Test

While the Walk and Turn test is one of the most reliable field sobriety tests, it is not perfect. There are several limitations to the Walk and Turn test that can impact its accuracy, including:

  • Medical Conditions – Certain medical conditions, such as inner ear problems or musculoskeletal disorders, can impact a driver’s balance and lead to a false positive.
  • Environmental Factors – The Walk and Turn test may be impacted by environmental factors, such as uneven surfaces or poor lighting, that can make it difficult to maintain balance.
  • Officer Error – The Walk and Turn test requires a properly trained officer to administer it, and errors in administration can lead to inaccurate results.

One-Leg Stand Test

The One Leg Stand test requires the driver to stand on one leg and count out loud for 30 seconds while keeping their balance. The officer is looking for specific indicators of impairment, such as swaying or losing balance.

How Does the One Leg Stand Test Work?

The One Leg Stand test works by measuring a driver’s ability to perform a divided attention task. The driver must listen to the officer’s instructions, maintain their balance while standing on one leg, and count out loud for 30 seconds. The officer is looking for specific indicators of impairment, including:

Swaying while standing on one leg.

  • Using arms for balance.
  • Hopping or putting the foot down.
  • Inability to count out loud for 30 seconds.
  • If the driver exhibits two or more of these indicators, it may indicate impairment.
  • Limitations of the One Leg Stand Test

While the One Leg Stand test is one of the most reliable field sobriety tests, it is not perfect. There are several limitations to the One Leg Stand test that can impact its accuracy, including:

  • Medical Conditions – Certain medical conditions, such as inner ear problems or musculoskeletal disorders, can impact a driver’s balance and lead to a false positive.
  • Environmental Factors – The One Leg Stand test may be impacted by environmental factors, such as uneven surfaces or poor lighting, that can make it difficult to maintain balance.
  • Officer Error – The One Leg Stand test requires a properly trained officer to administer it, and errors in administration can lead to inaccurate results.

While these three tests are the standard in Texas, it’s important to note that there are other tests that may be used in conjunction with them, such as the alphabet test or the finger-to-nose test.

What Happens If You Fail a Field Sobriety Test?

If you fail a DWI field sobriety test in Texas, the officer may arrest you and charge you with DWI. However, it’s important to note that field sobriety tests are not foolproof and can be challenged in court. There are many reasons why someone may fail a field sobriety test, such as nervousness, medical conditions, or environmental factors.

It’s also important to note that you are not legally required to perform a field sobriety test in Texas.

Wrapping up

DWI field sobriety tests are an important tool used by law enforcement officials to determine whether a driver is impaired. If you are pulled over and asked to perform a field sobriety test, it’s important to remain calm and follow the officer’s instructions. However, if you do fail a field sobriety test, it’s important to remember that you have the right to challenge the results in court. The tests are not infallible and can be challenged in court. Consulting with an experienced DWI attorney can help you understand your rights, evaluate the evidence against you, and develop a strong defense strategy. A skilled attorney can challenge the results of field sobriety tests by examining the administration of the test, the officer’s training, and any medical or environmental factors that could have impacted the results. It is important to remember that a DWI conviction can have serious consequences, including fines, license suspension, and even jail time, and having a knowledgeable attorney on your side can make all the difference in protecting your future.