Reasons Why Field Sobriety Tests Are Unreliable

Field Sobriety Tests, or FSTs, is the name given to a battery of subjective exercises promulgated by the NHTSA (National Highway Traffic Safety Administration) that ostensibly help the police officers to guess if a driver is impaired. While the name makes them sound clinical and official, these tests are among the most contentious elements of a DUI stop.

Standardized Field Sobriety Tests (SFSTs)

The three NHTSA validated tests that constitute the Standardized Field Sobriety Tests are:

  • The Horizontal Gaze Nystagmus Test: involves determining eye movement reaction through following an object, such as a pen, with the eyes
  • The Walk and Turn Test: designed to gauge an individual’s ability to understand directions and learn a sequence of steps while attending to physical and mental tasks, simultaneously
  • The One-Leg Stand Test

Some of the other tests in use, but without scientific validation from the NHTSA, are:

  • The Modified-Position-of-Attention Test, or the Romberg test: head back, feet together, and eyes closed for 30 seconds
  • The Finger-to-Nose Test: head back, eyes closed, and touching the nose tip with the index finger
  • The Alphabet Test: reciting the alphabet, all or part of it
  • The Finger Count Test: touching each finger of the hand along with counting at each touch
  • The Counting Test: backward counting, for a series of a minimum of fifteen numbers, starting with a number that does not end in a 0 or 5, and stopping at a number that also does not end either in a 0 or 5
  • The Preliminary Alcohol Screening Test: breathing into a preliminary or portable breath tester

As per the NHTSA, there is no pass or fail criteria in a field sobriety test, but it is up to the police to observe clues during the test. According to some NHTSA studies, the one-leg stand test shows an accuracy rate of 83 percent and the walk-and-turn test is accurate 79 percent of the time when conducted on individuals within the parameters of such studies.

These tests, however, were not validated by the NHTSA for individuals with injuries or medical conditions, as well as people above 65 years, or individuals overweight by 50 pounds or more. Simply put, true scientists use the term junk science for the three standardized field sobriety tests.

These field tests are completely optional and voluntary, with no penalty for refusing them, and a competent criminal defense lawyer should have no problem discrediting any sobriety test results if the prosecution uses them as evidence in a DUI case.

What is Impaired Driving?

Impaired driving, also known as Driving Under the Influence (DUI), or Driving While Intoxicated (DWI), refers to the criminal act of operating a motor vehicle while under the influence of alcohol or drugs, whether prescription and recreational, if the level of intoxication is such that the driver is unable to operate the vehicle safely.

The History of Field Sobriety Tests

In 1975, the United States National Highway Traffic Safety Administration (NHTSA) initiated research on testing people for impaired driving. From this research emerged a series of tests developed to assess suspected impaired drivers.

Within a span of six years, police officers in the country had started using many of the NHTSA validated standardized field sobriety tests to help them decide on arresting individuals suspected of impaired driving. While an early report outlined six tests, the Standardized Field Sobriety Test (SFST) battery was published in March 1999.

The Many Flaws of Field Sobriety Tests

The Tests Are Subjective in Nature

The accuracy and integrity of a test depend on measurable results and consistent application. FSTs are mostly like suggested exercises, with the results at the discretion of individual judgments.

This unscientific method opens up the possibility of different people drawing different conclusions from the same set of results, depending on their training and knowledge. These tests do not provide clear and factual evidence of an individual’s intoxication levels.

No Baseline Result for the FST

While conducting an FST, a police officer looking for suggestions of impairment, focuses on symptoms that are too broad and sweeping in their nature. The underlying assumption, however, is of how the subject would perform under normal circumstances. An individual’s normal physical condition that may affect their ability to maintain balance or walk straight, is not taken into account.

Stress and Other Factors Can Affect an FST

The results of an FST may be biased due to the uncontrolled environment combined with the confusion and anxiety of the driver. The time of the day and level of the ground could affect the driver’s ability to maintain balance, resulting in an adverse judgment by the police officer. Stress, induced by nervousness and listening to instructions, can cause people to make mistakes that they usually do not, in normal circumstances.

Choose a Skilled DUI Attorney in Colorado Springs

If you do not agree to take a field sobriety test, a police officer cannot insist upon you submitting to one. The test could also be used as evidence to implicate you in a DUI case. At Anderson & Carnahan, Attorneys at Law, we have provided experienced and aggressive legal representation to clients for over 50 years.

We encourage you to work with someone who knows Colorado DUI laws and also the most effective defense strategies to mitigate the situation as much as possible. Call us today at (719) 454-8059 or contact us online to schedule a free case evaluation, so that you can decide for yourself whether or not we are the right firm for you.

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