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DWI and Taking the Field Sobriety Tests


Have you ever sat around with a group of friends and talked about whether you would take the field sobriety tests (SFSTs) if requested? How did that conversation go? I am in a position where I get to have this conversation almost every single day of my life. Obviously, my position is that you should never take the field sobriety tests, even if you have had only one drink.   But it’s not just my opinion.  The recently dismissed APD SWAT Officer refused to take them on the night of his arrest.  I’ve heard a UTPD officer give a speech to a group of students informing them that they should never take the field sobriety tests if arrested.  Why? Because the SFSTs are designed for failure.

If you were going to design a test to make someone lose their balance, would you make them stand with their feet together or one in front of the other touching heel to toe? Would you make them stand on one leg with their arms up or down by their side? Would you let the person look up with their eyes open or closed? My first SFST training was in 2006 and I have had at least 2 classes a year each year since then.  Very rarely do the class participants pass any of the tests at 8 in the morning.

The standardized field sobriety tests are composed of three tests recommended by the National Highway Traffic and Safety Administration (NHTSA) in the late seventies/early eighties to be used by police throughout the US for screening drunk driving suspects. The three SFSTs are the HGN, the walk and turn, and the one leg stand.

The first SFST is called the Horizontal Gaze Nystagmus test (HGN). The HGN is also known as the pen test.  This test has the only hint of science of the three, but only if the officer performs it correctly, which is a seldom event.  Nystagmus is the involuntary jerking of the eye.  Nystagmus is present in our eyes all the time but not visible in most of the population. The HGN is a test where the officer moves the stimulus (the pen) horizontally at a certain speed from a specific distance to detect if nystagmus is visible. The officer is looking for three clues in each eye for a total of six.  If the suspect demonstrates four of six then the officer marks it as a failure.  About 48 known substances can cause nystagmus to be visible to the naked eye, one of which is alcohol.  There are also close to 40 different types of nystagmus.  Police are trained by other police, and do not have the ability to determine what causes the nystagmus, or what kind of nystagmus they are witnessing.  The NHTSA training manual specifies a very specific set of instructions on how the officer must conduct each “pass” of the eye regarding the time of each pass.  NHTSA also says the subject must be facing away from passing lights and that the officer’s overhead lights should be turned off during the test.  Any deviation from the NHTSA protocol compromises the test’s “validity”.  No medical professional uses HGN for anything.  No medical professional uses the presence of nystagmus to determine if a subject has had too much alcohol to drink.  I predict the use of HGN in our courts will be discontinued during my legal career.  It has also been my experience that many jurors do not give much weight to HGN.

Walk and Turn
The next test in the NHTSA SFST battery is the Walk and Turn test.  You may be more familiar with this as the walking of the line test.  Police refer to the Walk and Turn (WAT) as a “divided attention” test.  A divided attention test is one that involves a simultaneous mental task and physical task, like driving. This test is considered a divided attention because you have to perform the test while listening and remembering the complex instructions. Essentially, the instructions state that the subject must stand right foot in front of left, hands down at their side, then take nine heel to toe steps counting out loud without stepping off line, then do a complex turn using small steps and take another nine steps down the same line while looking down at the ground and not stopping once starting. In my opinion, the most important part of this test is the instruction stage where the officer has the suspect stand heel to toe with arms down by the side while the officer gives a very complex set of instructions.  In my experience, a subject fails the walk and turn during this stage almost every time.  Either the subject commits two “clues” in this stage or doesn’t comprehend the instructions and fails the test in the next phase, the walking phase.  There are eight clues the officer is looking for during this test, and if he sees two then it is marked as a failure.  The clues are: loss of balance during instructions, starts too soon, miss heel to toe, use arms for balance, step off line, wrong number of steps, stops while walking, and improper turn.  Two out of those eight and you’re done.  Most officers have a difficult time getting the instructions correct.  Remember that NHTSA says the tests must be performed as outlined in the instruction manual or their validity is compromised.  For example, the last instruction is the most overlooked by police and failure to give it will yield at least two clues.  The last instruction tells the subject that their first step (putting their back foot in front of their front foot) is step number one.  If the officer fails to give this instruction, then the subject is likely to take the wrong number of steps (they get to 9 sooner) and then they will turn in the wrong direction which creates an improper turn for clue number two. If you consider we all have different balance capabilities, listening skills, nerves, footwear, weather conditions, and roadside conditions, not many people have the ability to pass this test on the first try.  And one try is all you get to get it right.
One Leg Stand
The One Leg Stand (OLS) is the most difficult of the SFSTs.  In this test you are required to stand on one leg for 30 seconds and remain perfectly still!!! Are you kidding me? We are putting people in jail for not being able to stand on one leg for 30 seconds without moving, and the arms must remain down at your sides the entire time.  The OLS has four clues, two of which is a fail.  The four clues are putting your foot down, using your arms for balance, swaying, and hopping.  This is supposed to be an objective evaluation, but that’s impossible given each individual’s subjective limitations that affect abilities to do such a physically demanding task.  The officer gives a set of instructions while the subject stands with feet together and arms down by the sides, and states to lift one leg, whichever your more comfortable with, about six inches off the ground, keeping your foot parallel with the ground and counting 1001, 1002, 1003, and so on until the officer says stop while looking down at your foot.  The officer then times the test for 30 seconds noting all clues observed.  A major problem I see with officers conducting this test is interrupting the subject during the test with more instructions, and adding instructions that are not part of the NHTSA protocol.  Most often, officers say, “if you put your foot down, pick it back up and continue counting”.  This instruction is not supposed to be given unless and until a subject puts the foot down. Instead, many officers give it as part of the regular instructions which leaves the impression that it is ok for the subject to put their foot down and it won’t be counted against them.

Police officers always testify that all the SFSTs are simple tests.  That anyone can do them if they aren’t intoxicated.  This is why we try cases to juries.  Always remember to refuse these tests when offered by the officer, it is not illegal in Texas to refuse the sobriety tests.  The police cannot arrest you simply because you refuse the SFSTs, the police must have more evidence of intoxication to have probable cause to arrest you.  If you take these tests, chance are that you will fail, and then give the police the evidence they need to charge you with DWI and maybe secure a search warrant to draw your blood.  If you take these tests, call me, I have successfully defended hundreds of cases with SFSTs, and know what to do to help.