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Field Sobriety Tests

So you had a drink or two after a long, hard day at work. You get in your car, pop in a mint or a piece of gum, click the seatbelt on, check yourself in the mirror, and put it in drive. You don’t have far to go so you think everything is going to be smooth sailing all the way home. As you make the turn onto your street, you turn a little wide. Immediately, you see the cherries come on. Your heart jumps, your stomach drops, and your hands start sweating—you’re getting pulled over. You say to yourself: “Oh great! Now what?” A traffic stop can be a very intimidating experience, especially when a person has been drinking. This post deals with one aspect of a DUI investigation—field sobriety tests.

As a general matter, field sobriety tests are tools the officer can use to determine whether you are under the influence without actually testing your body for alcohol or controlled substances. In other words, they are evidence gathering tools used by officers to gather information to support their suspicion that you were driving under the influence. The results of these tests are used to establish probable cause to arrest and charge a person with DUI. What most people do not know is that you do not have to take the field sobriety tests, but you can be charged with a crime and lose your driving privileges for a long time if you refuse to submit to a chemical test if asked to take one by law enforcement.

Since alcohol is a central nervous system depressant, it slows down your body’s central nervous system. It also affects a person’s motor, cognitive and reasoning skills. Field sobriety tests are designed to divide your attention between two or more cognitive and physical activities or measure physical signs of intoxication. While there are many types of field sobriety tests, only three have been “standardized” after being studied by the National Highway Traffic Safety Administration (NHTSA). Those three standardized tests include (1) the horizontal gaze nystagmus; (2) the walk-and-turn test; and (3) the one legged stand test.

HORIZONTAL GAZE NYSTAGMUS: The horizontal gaze nystagmus test, or “HGN test,” is an eye test. The officer is looking for a quick back and forth motion of the eyeball. Normally, a person’s eye moves smoothly from one extreme to the other. In reality, the eye’s movement is a series of very small, incremental motions, which are involuntary. When a person’s central nervous system is slowed, however, the small motions become much larger and the eyeball jerks from one position to the next. The person’s eye movements start to move like a sprinkler---tick, tick, tick, tick…. That’s what law enforcement is looking for.

For each eye, the officer is looking for nystagmus (the tick, tick, tick) in three different ways: (1) the eye cannot smoothly pursue the stimulus; (2) there is visible nystagmus when the eye is brought all the way to the left or right; and (3) there is visible nystagmus before the eye reaches 45 degrees to the left or right. With the potential for three clues in each eye, the maximum (bad) score for the HGN test is six. If the officer observes a minimum of four clues, the test is considered a “fail,” which supports the officer’s belief that probable cause to arrest you exists.

Now, there are lots of types of nystagmus, and lots of things that can affect the HGN test. Alcohol is one cause of nystagmus, but nystagmus can also be caused by certain pathological disorders and diseases, medications (including caffeine, nicotine, and aspirin), circadian rhythms, congenital nystagmus and fatigue all can cause nystagmus. Despite these other possible causes of nystagmus, NHTSA has repeatedly stated that the HGN test can reliably estimate a 0.10 percent alcohol concentration 78 percent of the time. That report is good enough for government work. Consequently, the HGN test is routinely used to support finding probable cause to arrest and charge a person with DUI.

WALK AND TURN: The Walk-and-Turn test is commonly known as walking a line. The test, however, is not that simple. There four components to this test. First, the person is told to stand in a particular position and to listen to the instructions carefully. The person is told to put their left foot on a line with their right foot on the line in front of the left foot, heel-to-toe. The person is told to put their hands down at their sides and to keep them there throughout the entire test. The person is told to maintain this awkward position while the officer gives the rest of the instructions, and told not to begin the test until the officer says, “Begin.” Next, the person is instructed to take nine heel-to-toe steps on the line while counting each step out loud and without falling off the line or raising their hands. On the ninth step, the person is required to take a series of small steps while keeping the person’s foot on the line. Finally, the person must then take nine heel-to-toe steps back to the officer on the line while counting the steps out loud.

With this test, the officer is looking for eight different “clues” of intoxication: (1) the person cannot keep balance (i.e. steps away from the heel-to-toe stance, even in the “instruction” phase); (2) starting the walk before the officer says “begin”; (3) the person stops walking or pauses for several seconds; (4) the person misses a heel-to-toe step, usually by more than a ½ inch; (5) the person steps off of the line; (6) the person raises the arms while walking by more than six inches; (7) the person takes the wrong number of steps; and (8) the person turns improperly. According to NHTSA, a person fails the test and is likely to have an alcohol concentration of 0.10 percent or greater if the officer observes just two or more clues.

ONE LEG STAND: The last standardized field sobriety test requires the person to stand on one leg with their other leg straight out in the air about six inches. The person is first put into the “instruction” stance: feet together and arms down at the person’s sides. Once the officer says “begin,” the person is supposed to lift his or her foot about six inches, stare at the raised foot and count out loud until told to stop, about thirty seconds. One thousand one, one thousand two, and so on. The officer is looking for a person who sways while balancing, uses his or her arms for balance, hops, or puts his or her foot down before being told to stop. According to NHTSA, a person is about 65 percent likely to have an alcohol concentration of 0.10 or greater if the officer observes just two clues.

There are a number of “non-standardized” field sobriety exercises out there, which are used when it is impracticable or impossible to administer the three standardized tests discussed above. Examples include the finger dexterity test, counting backwards, reciting portions of the alphabet, picking up coins, the Rhomberg balance test, and a number of others. These tests have not been scientifically validated; however, officers use them to gather evidence of intoxication all the time.

SO DO I HAVE TO TAKE THEM? No! You do not have to submit to these field sobriety tests. These tests are designed to gather evidence against you. I have had discussions with several law enforcement officers about this, all of whom suggest that a person should always take these field sobriety tests. I think they’re dead wrong. Even if a person “passes” one or more of the field sobriety tests but fails a chemical test, the person is likely going to be arrested for DUI and taken to jail. On the other hand, in every case I have ever handled where a person submitted to these tests and did not successfully complete them, the officer has cited the person’s performance on the tests as grounds supporting probable cause to arrest and charge the person with DUI.

The reasons most cops want you to submit to field sobriety tests is that it makes their job easier. They have more information available to them to justify their decision to stop and arrest the person after the fact with their observations from the field sobriety tests. In order to politely decline taking them, I suggest following a four-step method:

1. Ask the officer if you have to submit to the field sobriety tests.

2. Ask the officer if the tests are 100 percent accurate.

3. Ask the officer if the tests can be used against you.

4. Finally, when the officer says that you do not have to take the field sobriety tests, the tests are not 100 percent accurate, and the results of the tests can be used against you, politely tell the officer you’d like to speak with an attorney before agreeing to submit to any testing.

Since there is no right to legal counsel before submitting to field sobriety tests, the officer is not going to stop the DUI investigation to let you make a telephone call to an attorney (even if you have one on speed-dial). The officer is going to then have to decide whether probable cause exists to ask you to submit to a chemical test, usually a hand-held screening device like the AlcoSensor or the SD-5. This decision will be then based only on the observations of driving conduct (which might be explainable in other ways) and the officer’s observations of your appearance and demeanor. These observations are much more subjective than a “standardized” test that is supposed to be an objective indicator estimating intoxication.

CHEMICAL TESTS ARE DIFFERENT! Keep in mind, however, that a chemical test (blood, breath, saliva or urine) is a very different animal. Under the current state of the law, it is a crime to refuse to submit to a chemical test. There are also administrative consequences for failing to submit to a chemical test.

Now that you know a little more about field sobriety tests, I hope you are in a better position if you ever find yourself looking at flashing lights in your rearview mirror. If you do find yourself in that situation, however, make sure to call an experienced DUI/DWI attorney right away. For questions or more information please feel free to contact me, Nick Thornton, at the Fremstad Law Firm, 701-478-7620, or