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Can I Challenge the Results of Field Sobriety Tests in Texas?

 Posted on September 22, 2020 in DWI

Plano criminal defense attorney DWI

If you were asked to do so right now, with no advance warning, could you stand on one foot while holding the other foot slightly off the ground for a full 30 seconds? Could you walk in a straight line—putting your foot heel to toe with every step—then turn around and come back on the same line, possibly without being able to look down at the line? If you were to have trouble with either of these exercises, federal authorities say that there is roughly an 80 percent chance that you are intoxicated.
Obviously, this was intended to be an exaggerated scenario, but in reality, the tests mentioned above are actually used by the police every day to test drivers who might be impaired by drugs or alcohol. The results of such tests are often presented as evidence against defendants facing charges for driving while intoxicated (DWI), despite the fact that these tests are not nearly as accurate as law enforcement officials would have you believe.

Standardized Field Sobriety Tests

There are three tests that are recognized by the National Highway Transportation Safety Administration (NHTSA) as effective in determining a driver’s level of impairment. Together, these three assessments comprise the Standardized Field Sobriety Tests (SFSTs). In addition to the one-leg stand and the walk-and-turn tests, the SFSTs also include the horizontal gaze nystagmus (HGN) test, in which the driver is asked to follow an object, such as the officer’s finger or a pen, with only eyes. In this test, the officer is looking for an involuntary jerking or movement of the eye, usually at the peripheral range, that is often seen as an indicator of intoxication. The three tests are typically administered together, and courts throughout the United States tend to accept the test results as proof—albeit rebuttable proof—that a driver is intoxicated.

Accuracy Concerns

The Standardized Field Sobriety Tests are certainly useful for police officers as they attempt to gauge a driver’s impairment level, but the tests are not close to perfect. As a matter of fact, the NHTSA acknowledges in training materials that the last time a large-scale validation study was conducted was in 1998. Even then, the tests were found to lead to “correct arrest decisions” about 91 percent of the time when the decision was based on all three tests combined. The accuracy was lower for each test on its own, and the walk-and-turn test was found to be the least reliable, with an accuracy rate of just 79 percent.
Using the NHTSA’s acknowledged best-case scenario, arrest decisions based on SFST results are made in 9 percent of cases. This means that just under one in 10 people, on average, are incorrectly charged with DWI due to the unreliable accuracy of SFSTs. It also means that the results of your test are not rock-solid evidence against you, regardless of what prosecutors and the police try to tell you.

What Causes Accuracy Problems?

Many different factors could significantly affect your SFST results. Some involve you, while others relate to the officer who administers the tests. From your end, health conditions and physical concerns could lead to “poor performance” during your tests. For example, you might have inner-ear issues or problems with vertigo, in which case, any tests that involve balance—including the walk-and-turn and the one-leg stand—are not good indicators of intoxication.
From the officer’s perspective, the tests must be administered in accordance with the procedures standardized by the NHTSA. Tests that are not conducted properly are even less reliable and are not generally admissible in court. Texas courts have also determined that SFST results that are presented as evidence in court must be accompanied by testimony that the tests were properly administered and compliant with NHTSA standards. This testimony, however, is not irrefutable, and it is subject to cross-examination by your attorney.

Contact a McKinney DWI Defense Attorney

If you are facing DWI charges in Texas, and you are concerned that your SFST results are being used against you inappropriately, contact one of the experienced Collin County DWI lawyers at the Law Offices of Biederman & Burleson, PLLC. Not only have our attorneys completed the NHTSA’s training program on how to administer the SFSTs properly, but Attorney Hunter Biederman is certified to teach the course to police officers. This means that we know how the tests are supposed to work and what their limitations are. Call us today at 469-333-3333 to schedule a free consultation with a member of our skilled legal team.



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