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Purpose of Field Sobriety Testing

Interviewer: What is the purpose of the field sobriety test?

Kevin Roach: The purpose of the field sobriety test is to determine whether someone is impaired while driving.  The field sobriety test was established by the National Highway Traffic Safety Administration with very specific guidelines for police officers to follow when administering this test. The field sobriety test that North Missouri police officers most frequently utilize is divided into basically three tests: the gaze nystagmus test, the one-leg-stand test, and the walk-and-turn test.

Interviewer: When they call it a field sobriety test, is it an actual test, so to speak?

Kevin Roach: Yes.  It is a test to determine if the driver is impaired.

Administration & Refusal of Field Sobriety Tests

Interviewer: During the process when someone gets pulled over, at what point is it administered to the individual?

Kevin Roach: Once the police officer suspects that you're driving under the influence, he'll ask that you exit the vehicle, and will then typically proceed with the field sobriety test.

Interviewer: Now, are you able to refuse this test?

Kevin Roach: Absolutely.  You can definitely refuse the field sobriety test.   In my opinion, it's probably better to refuse the test since they seem to be designed for people to fail. I would say maybe 1 out of 1,000 people might pass the test. The overwhelming majority of people that take the test fail.

Scientific Basis Behind FST’s

Interviewer: Is there a scientific basis behind these tests?

Kevin Roach: Not really. The National Highway Traffic Safety Administration, the NHTSA, established these very specific guidelines for the police officers to follow in-order to ensure the intended accuracy; but I’m sure it can be argued whether or not there's any scientific backing on this.

Common Misconceptions Regarding Field Sobriety Tests

Interviewer: What do you say are some of the more common misconceptions that you can have about the field sobriety test?

Kevin Roach: One major misconception would apply for the gaze nystagmus test, the HGN test.  Most people think that the officer is testing them on whether they can follow the police officer's finger and instructions; but, the officer is actually looking at the person's eyeballs.  When someone is intoxicated, their eyeballs will make involuntary jerks and gazes towards the sides. An officer is looking for that involuntary jerking as a sign of intoxication. With this common misconception, almost every client becomes surprised to learn that this portion of the field sobriety test was failed.


Interviewer: Are people videotaped while they are performing these tests?

Kevin Roach: Sometimes. This is actually becoming more and more common in the St. Louis area.  Quite a few municipal police departments that have video cameras installed in their patrol cars.  Every so often, the video can be used to help your case.

Contact a St. Louis DWI Defense Lawyer Today

Kevin J. roach is a St. Louis DWI defense attorney who has defended thousands of DWI and DUI cases in the St. Louis Metro area. Call us today at (636) 519-0085 or (866) 519-0085 for your Free Consultation!

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