- Evan M. Howard
The DWI Process in Missouri. Part 3: The Field Sobriety Test.

By this time, the officer has asked you to step out of the vehicle and is asking if you’d submit to a field sobriety test. Unlike the request to get out of the vehicle, the officer’s request for you to submit to a field sobriety test if literally a request. You are not required to take a field sobriety test. Regardless of what the officer tells you, if you refuse to take the field sobriety test, there will be no legal consequences. Don’t take legal advice from a police officer anyway! This is not the case for the breathalyzer test though, you will face consequences for refusing to give a breath test and we’ll discuss that more later.
The officer already believes you’re driving while intoxicated, so why even ask for you to take the field sobriety test? Well, it’s quite simple; it’s free evidence against you given to the officer.
So you’re asked if you’d like to give the officer additional evidence against you and if you refuse there will not be any consequences, let’s hope you politely refuse to take the field sobriety test but for this articles sake we’ll say you agreed to the test.
So what exactly is the test? The Field Sobriety Test was established by the National Highway Traffic Safety Administration. The three most common tests given by officers are the Horizontal Gaze Nystagmus Test, the One-Leg Stand test and the Walk and Turn Test. While the National Highway Traffic Safety Administration claims these tests are supposed to test your abilities to operate a motor vehicle, in all reality these tests are designed to make you fail.
Think about it, the tests are given in the middle of the night where it’s dark. You’re on the side of the road, probably standing on gravel or an uneven surface. In addition, there are other cars driving by you. It’s a scary situation to be in in the first place, now adding in all these other factors it’s almost impossible to pass this test sober let alone after a couple of drinks.
The National Highway Traffic Safety Administration’s Standardized Field Sobriety Test Manual is an extremely detailed manual that require officers to follow in order for the test to be administer correctly, but, as you’ll soon learn, even when the tests are administered correctly it does not guarantee its accuracy. In order to fail the Field Sobriety Test, you only have to mess up on two of these three Tests.
Horizontal Gaze Nystagmus Test
This Test is based on basic human biology that shows an involuntary twitch which occurs whenever a person looks sideways at an angle greater than 45 degrees. The interesting thing is, when a person has a high level of BAC, that biological twitch actually occurs when the person is looking sideways at an angle less than 45 degrees. Sound complicate? Well, it is. And how do you expect an untrained officer to notice a slight twitch in an eye at 43 degrees vs 45 degrees?
The HGN Test requires the officer to hold an object twelve to fifteen inches from the tester’s nose and slowly move the object from one side of the eye and back to the center of the nose. The Manual further states that the object should be moved two seconds from the nose to one eye and two seconds back to the center of the nose.
The officer is looking for (1) if your eye moves smoothly or if it jerks noticeably, (2) are your eyes jerking when you move them from side to side, and (3) do your eyes start jerking before they reach the 45 degree angle. Wow, that’s a lot for an untrained officer to be looking for at night, in the dark, on the side of a road, standing in gravel with cars speeding by.
Personally, I have seen officers mess this up in so many different ways. First, they’ll never hold the object, usually a pen, twelve to fifteen inches away from the test’s nose. Second, the officer won’t take the two second from nose to eye and back to nose. What will most likely happen is the officer is going to take their pen and whip it over to the side of your face and then back to the other side of your face.
More than likely the officer isn’t going to administer the Test correctly, and remember, even if the test if administered correctly it does not guarantee its accuracy. The National Highway Traffic Safety Administration, in its own Manual, states the HGN Test only has a 77% accuracy rate when administer correctly.
One-Leg Stand Test
Before administering the test, the officer must explain the test to the tester and must also demonstrate what the officer is expecting. This is a divided attention test, meaning its asking for the tester to divide his or her attention between the mental task of following instructions and the physical task of balancing on one leg.
The NHTSA Manual requires the tester to raise one or more of their arms more than six inches from their side in order to fail the Test for “using their arms to balance.” The One-Leg Stand Test, in accordance to the NHTSA Manual, requires the officer to look for “swaying, using arms for balance, hopping or placing foot down” while the tester balances with one leg approximately six inches in the air. The Manual defines “swaying motion” as a side-to-side or back-and-forth motion.
Here, this test is so subjective, there is no way you’re going to meet the officers expectations; they already have a biased mind and are just looking for the slightest slip up. And as far as accuracy, the One-Leg Stand Test is only about 60% accurate in determining if an individual is intoxicated or not.
Walk and Turn Test
This Test is also a divided attention test requiring the tester to divide his or her attention between following instructions and performing a physical task. During the Test the officer is required to have the tester stand stationary heel to toe while the officer explains and demonstrates the instructors for the test. The NHTSA Manual states that the tester should take nine heel to toe steps, take series of small steps while turning around, and take another nine heel to toe steps back.
The NHTSA Manual requires the officer to demonstrate to the tester what the officer is requiring. If the officer fails to provide adequate directions, the tester isn’t going to know what is expected of them. The Manual requires a fair and accurate description of the test and then requires the officer to actually perform the test.
During the explanation, in real life, you’ll see the officer only take about three steps and then complete a turn. Apparently, courts have ruled this is allowed. But the big thing you’ll notice is during the officers turn, they will more than likely not take that “series of small steps” as required by the Manual.
This might sound nit-picky, but if the tester isn’t aware of what he or she is supposed to do, they’ll end up “failing” the Test according to the officer. Plus, the officer is watching your every move and trying to find the slightest mistake on your end; the playing field should be level for both parties in my opinion. And in case you were wondering, the Walk and Turn Test only has a 60% accuracy rate according to the NHTSA Manual.
Remember, if you refuse the Field Sobriety Test, there will be no consequences. Also remember, these tests are designed to make you fail. Stay tuned for the fourth part of this series, Part 4: The Breathalyzer, to Blow or not to Blow?
For immediate help, guidance or advice, contact Howard Law at (314) 325-9868.
Next: The DWI Process in Missouri. Part 3: The Breathalyzer, to Blow or not to Blow?
About The Author
Evan M. Howard is the managing attorney for Howard Law, a St. Louis business law and criminal defense law firm based in Clayton, Missouri. Focused on giving honest, quick and effective representation to all its clients. With a background in business and experience dealing with tough criminal prosecution cases, Howard Law is prepared to help guide you through your legal matter.
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