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How Can I Pass a Standard Field Sobriety Test?

Kaylind Landes
9 minute read

We’ve all seen shows where a person is pulled over on the side of the road and has to demonstrate to the police that they’re not drunk. Maybe it’s counting backward, walking in a straight line, or something similar.

In real life, these demonstrations are called standard field sobriety tests (SFSTs), and are indeed how Oklahoma officers identify impaired drivers. But they aren’t random games an officer pulls out of thin air—there are three specific tests that have been approved by the National Highway Traffic Safety Administration (NHTSA) for use by law enforcement officials in Oklahoma.

What are Standard Field Sobriety Tests (SFSTs)?

NHTSA has created guidelines for three approved SFSTs: the Horizontal Gaze Nystagmus, the Walk and Turn, and the One-Leg Stand. Per the NHTSA Instructor Guide, these particular tests were chosen because, “Based on a series of controlled laboratory studies, scientifically validated clues of alcohol impairment have been identified for each of these three tests. They are the only Standardized Field Sobriety Tests for which validated clues have been identified.”

It’s important to know that these tests are tools to help an officer see visible signs of impairment and are not pass/fail. Here’s how it usually happens: If there is probable cause (this is essential) to pull you over and suspect you are impaired, the officer will most likely administer one or more of these SFSTs to determine your level of impairment. If the officer determines that you did not perform the test(s) properly, you’ll be arrested for driving under the influence (DUI). If you are arrested for a DUI, Oklahoma law mandates that you must submit to a chemical test (such as a breathalyzer) within at least two hours of driving, which can further confirm your level of impairment.

In other words, whether you are arrested can hinge on how well you perform on an SFST. Do they work? Yes, but they’re not 100% accurate. Recent studies show a high percentage of correct evaluations by the officer, but only when the tests are administered correctly. And even then, there is a margin of error. Some people, such as alcoholics with a high tolerance, will display no signs of impairment while others, such as those taking certain medications, will seem more impaired than they actually are.

It can help tremendously to know what to expect if you’re pulled over for a DUI and offered these standard field sobriety tests. Learning what each test is, what officers will be looking for, and how you can perform them properly might save you from an arrest.

Horizontal Gaze Nystagmus: What to Expect

Horizontal Gaze Nystagmus (HGN) is an involuntary jerking of the eyes as they follow a stimulus (such as a penlight or pencil) from side to side. The NHTSA states that this is the most accurate of the standard field sobriety tests, which is why it is often the first and most commonly used test in the field by police officers.

How HGN Is Performed ​​

The officer will hold the stimulus slightly above your eye level and about 12-15 inches from your nose. You’ll be instructed to stand with your feet together and hands at your side. Keeping your head still, you must follow the stimulus with your eyes only (in other words, without turning your head) as it moves from side to side.

3 Impairment Clues Officers Will Be Looking For

(Note the officer will be looking for three separate clues in each eye, for a total of six clues.)

  1. Lack of smooth pursuit (if your eyes jerk or bounce as they follow the stimulus)
  2. Distinct and sustained Horizontal Gaze Nystagmus at maximum deviation
  3. Onset of Horizontal Gaze Nystagmus prior to 45 degrees

Typically, the more impaired you are, the sooner the nystagmus will appear. After you complete all three tests in each eye, the officer will total the clues. If your “clue count” is four or higher, the officer will assume that your blood alcohol content (BAC) is at or above .08. This is based on recent research, which also states that using these HGN clues will allow officers to correctly classify about 88% of people.

Walk and Turn: What to Expect

Walk and Turn (WAT) is a divided attention test that requires you to simultaneously perform both mental and physical tasks. For the mental tasks, you must be able to comprehend verbal instructions, process information, and remember what was asked of you. The physical tasks include balance and coordination; you cannot fall or stumble while standing still, walking, or turning. In an ideal situation, the Walk and Turn test is conducted on a firm, level, non-slippery surface.

How WAT Is Performed

The officer will have you stand on a line and assume a heel-to-toe position. Then, you will be asked to keep your arms at your side and listen while the officer gives you instructions. This is important—you must keep your balance and hold still while listening. Do not start walking until the officer tells you to do so. After the officer explains the test and gives you the command to start, you will take nine steps forward, touching heel to toe; after the ninth step, you will turn, and take nine heel-to-toe steps back to where you started. (The officer will demonstrate the test to you before you begin.) If you are wearing any type of unusual footwear, such as flip flops or heels, you can remove them to perform the WAT.

8 Impairment Clues Officers Will Be Looking For

  1. Cannot keep balance while listening to instructions
  2. Starts too soon
  3. Stops while walking
  4. Does not touch heel to toe (more than ½ inch between)
  5. Steps off the line
  6. Uses arms to balance (6 or more inches from your sides)
  7. Improper turn
  8. Wrong number of steps

Typically, an intoxicated person cannot multitask. For example, you may be able to listen to instructions, but not keep your balance (or vice versa). Also, you may be able to walk heel to toe, but you won’t remember how many steps to take.

The NHTSA Instructor Guide references recent research that tells police officers if a subject (you) exhibits two or more clues on the WAT, or can’t complete it, your BAC can be estimated to be at or above .08 with a 79% accuracy rate.

One-Leg Stand: What to Expect

The One-Leg Stand (OLS) is another divided attention test that requires you to perform mental and physical tasks. Like the WAT, there are two stages: instructions and action. In this case, the action stage involves keeping your balance and counting out loud.

How OLS Is Performed

The officer will ask you to stand with your hands by your side and your feet together while they instruct you on how to perform the test. While the officer explains the instructions, you must stand still and listen. When they prompt you to begin, start by raising one leg (either leg) about six inches from the ground. You will keep your leg raised and your hands by your side as you count out loud—”one thousand one, one thousand two, one thousand three,” etc.—until the officer tells you to stop. Again like the WAT, the officer will demonstrate the test to you before you begin and you are allowed to remove shoes such as high heels.

4 Impairment Clues Officers Will Be Looking For

  1. Sways
  2. Uses arms to balance (6 or more inches from your sides)
  3. Hops
  4. Puts foot down

Keep in mind police officers know that time is critical in this test and research has shown that an intoxicated person (BAC of .10 or higher) can balance for up to 25 seconds, but not often 30 seconds. That’s why the officer will also keep their own time while you are counting out loud.

If your clue count is two or higher, police officers will assume your BAC is at or above .08 (with an 83% accuracy rate).

SFSTs Are Voluntary in Oklahoma

If you are pulled over for a suspected DUI and asked to perform one of the standard field sobriety tests, you are well within your rights to tell the officer that you do not want to. You can also stop taking the tests at any time. Just remember that if you decide to take these tests and don’t perform well, that is evidence that will be used against you in court.
If you’ve been charged with a DUI, either because of a poor SFST performance or another situation, contact us for a free case evaluation. We have been helping people put their DUIs behind them for over 15 years.