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What to Know about Field Sobriety Tests in Texas

Most of us are aware of field sobriety tests. We may have taken them ourselves, or seen them depicted in the movies or on TV. Despite this general knowledge, you may be surprised to learn just how inaccurate field sobriety tests can be. Even though these tests are known to be inaccurate, they still play a role in Texas DWI arrests. 

If you've been charged with a DWI in Texas and you think because you failed a field sobriety test, don't think that you should “take a deal” or choose not to fight this conviction, think again. An experienced DWI attorney knows where to look for the weak spots in the state's case. As you will learn, these field sobriety tests are just one more place where police officers can fail to follow the proper protocol, giving you more fuel for your defense. 

Types of Texas Field Sobriety Tests

Texas law enforcement officers generally use one of three types of field sobriety tests: the Walk and Turn Test, the Horizontal Gaze Nystagmus Test, and the One-Leg Stand test.

One-Leg Stand Test

This test is fairly straightforward. During a One-Leg stand test, the officer will ask that you stand with one foot about six inches off of the ground. You will be asked to count during the time your foot is off the ground. You will be timed for a period of thirty seconds. During a One-Leg stand test, the officer will be watching you closely for:

  • Using your arms to help you balance
  • Rocking /Swaying while balancing
  • Putting your foot back down due to loss of balance
  • Hopping up and down in an attempt to maintain your balance

Alcohol can generally impair a person's ability to maintain balance. The One-Leg Stand test is an attempt to monitor all balance indicators to detect the presence of impairment from alcohol or other drugs.

Horizontal Gaze Nystagmus Test

This test involves an officer tracking your eyes. During the Horizontal Gaze Nystagmus (HGN) Test, an officer will hold an object and move it slowly back and forth, asking you to follow that object with your eyes. During an HGN test, an officer will be watching you closely for:

  • Failure to follow the object with your eyes
  • Jerking of your eyes when the object reaches a certain angle

Nystagmus refers to an involuntary jerking movement that our eyes make. This happens naturally when we look to the side. However, under the influence of alcohol, this jerking motion is supposed to be exaggerated and visible to a trained law enforcement officer.

Walk and Turn Test

The Walk and Turn Test is another way for law enforcement officers to measure your coordination and balance in order to detect impairment from alcohol or drugs. During a Walk and Turn Test, an officer will ask that you walk a particular distance, from heel to toe, without stopping. During this test, you must keep your eyes cast down to the ground and your arms at your sides. Once you complete the distance, you must turn, and walk back in the opposite direction, maintaining the heel-to-toe movement. During the Walk and Turn Test, the officer will be watching you closely for:

  • Stopping at any time
  • Failing to follow the directions properly, including the correct number of steps
  • Failing to walk heel-to-toe
  • Stumbling or stepping out of the straight line in any way
  • Using your arms to balance yourself
  • Failing to properly turn

Are Field Sobriety Tests Accurate?

Field sobriety tests are so ingrained in DWI arrests across the country that we sometimes assume they must be extremely accurate in order to play such a vital role in intoxicated driving enforcement. However, this is not the truth. 

Various studies have examined the efficacy of field sobriety tests. The National Highway Traffic Safety Administration (NHTSA) has evaluated the accuracy of these tests in a variety of studies. The first study, conducted in the 1970's, found that by itself, the One-Leg Test was 65% accurate; the HGN test was 77% accurate; the Walk and Turn Test was 68% accurate. 

Based on the fact that test tests did not appear to be all that useful in actually detecting intoxication, the organization recommended that law enforcement officers combine the tests and administer all three, in an attempt to better detect impaired driving. Some follow-up studies were conducted on the efficacy of all three tests used simultaneously. These studies were conducted in various states and found that they yielded a “correct arrest decision” anywhere from 86-95% of the time. 

However, in training materials, the NHTSA still discloses that the tests do not solid evidence-based results for accuracy. The organization instructs law enforcement to “reference in court whenever possible” that the HGN test was found to be 88% accurate, the One Leg Stand test was found to be 83% accurate, and the Walk and Turn Test was found to be 79% accurate. 

These tests are designed to be performed by trained law enforcement officers under ideal conditions. Is this always the case with a Dallas/Fort Worth area DWI stop? Of course not. There are a wide variety of environmental factors that can affect the accuracy of these field sobriety tests.

Can A Field Sobriety Test Be Wrong?

Absolutely. A perfectly sober person can fail a field sobriety test for a number of reasons that have nothing to do with intoxication. So many different factors are at play during these tests, and any number of these can affect the ultimate result. These can include, but are not limited to:

Environmental Factors

Weather: precipitation, storms, high winds, and other weather conditions can severely affect an individual's ability to perform a field sobriety test. These factors create a natural barrier to the ability to hear an officer when he or she is instructing you on how and when to perform certain actions. They also affect your ability to maintain balance, another key factor that law enforcement officers are examining during these tests.

Biological Factors

There are many medical conditions that can affect your ability to perform a field sobriety test. These can include conditions that affect your legs, inner ear, eyes, and more which make it more difficult to balance. Certain physical conditions, including temporary and permanent disabilities, may make it difficult to perform the One Leg and Walk and Turn Tests. It is essential to remember that these tests were designed to be used on healthy, able-bodied individuals, which make them inapplicable for a vast segment of the population.

Psychological Factors

Getting pulled over for a suspected DWI is a jarring experience. Seeing flashing blue and red lights in your rearview mirror can be a terrifying experience, even if you weren't doing anything wrong. Our behavior can be dramatically altered just because we are in the presence of law enforcement officers. Numerous studies have demonstrated the rate at which suspects in criminal cases give false confessions to the cops, which perfectly highlights how simply being in the presence of these types of authority figures can impair our ability to communicate rationally. Anxiety can play a huge part in taking a field sobriety test and can cause you to lose balance and/or have trouble following directions.

Improperly Conducted Test

In order for these tests to meet the already established low bar of efficacy that they have when performed under ideal conditions, the individual administering the test must do so properly. If the law enforcement officer gives instructions properly, fails to give a necessary instruction, or otherwise fails to meet any of the elements necessary to communicate how to perform the test, it is impossible for you to accurately perform. Even a well-trained officer may struggle with communicating these instructions when dealing with issues such as a language barrier or other obstacles. With the increase in smart home surveillance systems, ride-share cameras, and police body cams, we have access to better records of DWI arrests than ever before. If the police officer failed to conduct a test properly or violated your rights in any way, this is more ammunition for your attorney to use against the state.

DWI Defense in Dallas/Fort Worth

If you or someone you love is facing DWI charges in Plano, Texas, or anywhere in the Dallas/Fort Worth area, fight these charges with an experienced criminal defense attorney by your side. No matter what the circumstances of your arrest, you deserve a shot at preserving your freedom and your future. If you think you've “failed” a field sobriety test or a BAC test, think again. This is just preliminary evidence that the state will use against you. It is not the final word on your guilt or innocence. Carl Ceder has dedicated his career to defending Texans and getting them the best possible outcome. Contact the office today online or give a call at (469) 900-0000 so we can begin fighting together.