Understand the Faults Behind Field Sobriety Tests

Field sobriety tests are commonly used by police to determine if a driver is intoxicated. However, there are many concerns about the validity of these tests.

Common Types of Field Sobriety Tests

Understand the Faults Behind Field Sobriety TestsA standard field sobriety test consists of three separate tests:

  • The One-Leg Stand Test: The subject is asked to stand in front of the officer and lift one leg off the ground while maintaining balance for approximately 30 seconds.
  • The Walk-And-Turn Test: The subject is asked to walk heel-to-toe in a straight line.
  • The Horizontal Gaze Nystagmus Test: The officer will hold an object close to the subject’s face. The officer will then tell the subject to keep their eyes on the object as they move it in front of them.

Through each of these tests, the officer examines the subject’s balance, coordination, ability to follow instructions accurately, and any additional signs of impairment due to intoxication.

Faults of Field Sobriety Tests

Failing one or more of these field sobriety tests can lead to a DWI charge. However, there are many questions concerning the accuracy of these tests.

One main concern is test reliability. The horizontal gaze nystagmus is considered the most accurate of the three main tests but only has a 77% accuracy rate. This raises concern about how people can be given criminal DWI charges on an unreliable basis.

Another fault of field sobriety testing is the way the test is administered. The officer may fail to properly administer the test due to a lack of training or a misstep in the procedure. Officer bias may also lead to inaccurate results of the tests.

The driver may also have mental or physical handicaps that prevent them from performing the tests accurately. If the officer did not ask about such conditions before administering the tests, this could lead them to determine the driver is under the influence when they are not.

Why are Field Sobriety Tests Almost Always “Failed?”

It is estimated that about one-third of sober people fail field sobriety tests. In addition to the reasons listed above, other factors can lead you to fail a field sobriety test, including:


There is no denying that being asked to perform a field sobriety test is an anxiety-inducing situation for most people. The physical symptoms of anxiety often manifest as muscle tension, shakiness, and other uncontrollable movements. These symptoms can be misinterpreted by the officer administering the test and lead them to determine you are under the influence.


If you have been driving for an extended period of time, you may be experiencing fatigue. Like anxiety, this can lead to muscle tension in your legs that prevents you from walking straight or keeping balanced. Certain prescription medications may also cause these side effects of fatigue. The officer may perceive this as a sign of intoxication.


This could result from being unable to hear the officer due to loud noise in the surrounding area or from the officer explaining the instructions in a way that was confusing and unclear. In both of these cases, misunderstanding may lead you to make mistakes during the tests.

How to Argue Against a Failed Field Sobriety Test

Many experts challenge the legitimacy of field sobriety tests since they are not foolproof methods of determining a driver’s level of intoxication. The role of officer discretion in field sobriety testing can lead to many instances of inaccurate findings.

If you are facing DWI charges following a failed field sobriety test, you are encouraged to challenge the results. Contact a skilled DWI attorney to help you fight your case.

Experienced DWI Defense Serving North Texas

Contact Deandra Grant Law today to schedule a consultation. We are fully committed to helping challenge field sobriety test results in order to help you reach a positive outcome.


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