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What are dui field sobriety tests and how do you defend against them?

What are dui field sobriety tests and how do you defend against them?
Axelrod & Associates, P.A.

What are DUI field sobriety tests?

When you think of a DUI arrest, you may picture a person standing on the side of the road, with blue lights flashing and a police officer standing in front of them, leaning their head back while touching their nose.

Or, you may picture a person walking an imaginary straight line on the side of the road, heel to toe, as a police officer watches…

Both are DUI field sobriety tests used by police officers, but only one is a “standardized field sobriety test” that should be admissible in court. Below, we will cover the basic information you need to know about DUI field sobriety tests in SC, including:

  • What DUI field sobriety tests are,
  • The difference between standardized and non-standardized field sobriety tests, and
  • How to defend against DUI sobriety tests in court.


DUI field sobriety tests are designed to tell a police officer whether a driver’s blood alcohol level is greater than .08. Designed poorly, though…

If all three standardized field sobriety tests are 1) administered properly and 2) administered together, NHTSA says they have a 91% accuracy rate. But do they really? Or are the police confusing a “coordination test” with a “blood alcohol test?”

The result may be accurate if we assume:

  1. The officer is administering them properly, which is often not the case (an officer moving his finger in front of a felony DUI suspect’s eyes as the suspect is lying in a hospital bed with head injuries is not a valid HGN test, for example), and
  2. The suspect does not have any other physical reason for performing poorly on the tests.

There are literally hundreds of medical issues that can cause a person to perform poorly on any or all of the field sobriety tests, and most police officers 1) do not check for them and 2) don’t care anyway.

For example:

  • Medical causes of nystagmus (involuntary jerking of the eye that the officer is looking for in the horizontal gaze nystagmus (HGN) test,
  • Back, leg, knee, foot, or other related problems,
  • Overweight people,
  • People with tendonitis, arthritis, or other inflammatory diseases,
  • Vertigo or other conditions that affect a person’s balance,
  • Stiff legs and joints from driving for long periods of time, or even
  • An inability to follow instructions precisely.

What if you are a fortunate, young, educated, healthy, athletic person who doesn’t have any medical issues at all (yet)?

Even an average, ordinary person with normal balance and motor skills can easily “fail” the field sobriety tests while stone-cold sober. Why?

It is subjective.

There are a number of “clues” that the officer is looking for on each field sobriety test, including things like whether the person waited for the officer to say, “begin,” or whether the person made their turn at the end of the walk and turn test exactly the way the officer demonstrated it.

If the officer thinks you are DUI, they can and will “fail” you on the field sobriety tests. And, if the officer doesn’t think you are DUI, they aren’t going to give you the tests in the first place…

Standardized field sobriety tests, when administered properly, can indicate that a person is intoxicated. Or the results may indicate that a person has health problems, can’t follow instructions, or suffers from one of the hundreds of health issues that would cause them to “fail” a field sobriety test.

Standardized Field Sobriety Tests (SFSTs)

There are only three standardized field sobriety tests that NHTSA has approved as having any evidentiary value:

  • The horizontal gaze nystagmus (HGN) test – the officer moves a pen or a small light back and forth in front of your face, and, as you follow it with your eyes, the officer looks for nystagmus (involuntary jerking of the eye that can be caused by many medical conditions other than intoxication).
  • The walk and turn test – after standing still with your right foot in front of your left foot as you listen to the officer give the instructions, you walk a straight line taking nine steps, touching heel to toe each time, turn around using the exact method the officer demonstrates, and take nine steps back to your starting point.
  • The one-legged stand test – after standing still with your feet together as the officer gives the instructions, you lift one foot, holding it six inches from the ground and parallel to the ground as you count, one-one-thousand, two-one-thousand, until the officer tells you to stop counting.

Non-Standardized Field Sobriety Tests

There are a number of non-standardized field sobriety tests that police officers still use today, although they have zero value in determining a person’s BAC, and the NHTSA instruction manual says that officers should not use them unless it is impossible to administer the other tests.

These include:

  • Holding your head back as you stand with your eyes closed,
  • Touching your nose with your finger as you stand with your eyes closed,
  • Counting backward from one arbitrary number to another arbitrary number,
  • Saying your alphabet from a certain letter and stopping at another letter,
  • Saying your alphabet backward,
  • Touching your fingers to your thumb as you count, or
  • Variations on these and other themes.


First, you decide whether you need to fight against them – in many cases, if you performed fairly well (despite the officer saying you “failed the test”) or if you have a valid medical reason for not performing well, the video of the field sobriety tests may help you.

If the video and officer’s testimony regarding the FSTs are harmful to your case, you may be able to get them excluded based on the officer failing to perform the tests correctly (per the NHTSA training manuals), the officer administering non-standardized tests, or the officer not administering all standardized tests together (the SC Supreme Court held in State v. Sullivan that the HGN test is not sufficiently reliable to be admissible in court unless the other tests are administered with it, for example).

If the FSTs are going to be admitted in your trial, your DUI attorney can demonstrate why they are not reliable by:

  • Getting the officer to repeat the instructions for each field sobriety test to the jurors,
  • Getting the officer to demonstrate each field sobriety test for the jurors, and
  • Asking the jurors to try them for themselves during deliberations – any jurors who are overweight, older, have trouble with the instructions, have medical nystagmus, or have medical problems will immediately understand how and why the FSTs are not a reliable indicator of a person’s BAC.


If you have been charged with DUI, DUAC, felony DUI, or a DUI-related offense in SC, contact a DUI defense lawyer on the Axelrod team immediately – we may be able to get your case dismissed, you may be able to avoid a license suspension, and you may have defenses that you are not aware of.

Call Axelrod and Associates now at 843-916-9300 or email us to talk with a Myrtle Beach, SC DUI defense attorney today.

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