The National Highway Traffic Safety Administration (NHTSA) has set out the guidelines for the three standardized field sobriety tests (SFSTs). The three tests are the Horizontal Gaze Nystagmus test (HGN), the Walk-and-Turn test (WAT), and the One Leg Stand test (OLS). These are the only tests that have had field studies completed to determine the validity of the tests as they relate to the detection of people under the influence of alcohol. The other tests, including touching your nose or reciting the alphabet, have no validity studies to back them up.
Field sobriety tests are psychophysical or divided attention tests, used to assess impairment. The police officer is trained to start psychophysical tests as soon as the officer makes contact with you, the driver. For example, the officer will ask for your driver’s license, registration and proof of insurance at the same time. The officer will then ask you where you are coming from as you retrieve these documents in an effort to confuse and distract you. This divided attention task requires the driver to mentally process (a mind task) the request for three different items while retrieving the requested items (a body task). The three most significant psychophysical tests are the three “scientifically validated” structured tests known as the Standardized Field Sobriety Tests.
Horizontal Gaze Nystagmus
Nystagmus is defined as an involuntary jerking of the eyes. It is something the person being tested will not be aware of during the administration of the test. Involuntary jerking of the eyes will become more noticeable as a person’s blood alcohol level rises.
The Horizontal Gaze Nystagmus test is considered the most accurate of the field sobriety tests by the National Highway Traffic Safety Administration. This test is not admissible in Colorado to show any specific level of impairment, but rather to show impairment in general. There are six total clues. If four or more clues are evident, the Horizontal Gaze Nystagmus test is allegedly 77% accurate in detecting a person with a blood alcohol level in excess of 0.10. The officer will be looking for three separate specific clues in each eye. Thus, the total of six clues.
The officer is supposed to use a small stimulus to move back and forth in front of your eyes. There should be two sets of passes for each clue for a total of six passes in the testing stage.
Before starting the testing phase of the test, the officer is supposed to have you remove any glasses you are wearing. Then, the officer will make two passes using a small stimulus to check for equal tracking of the pupils. If your pupils do not track equally, there may be a medical problem. The officer is also supposed to check your pupils to ensure they are the same size.
The officer will make two passes each looking for lack of smooth pursuit, checking for distinct and sustained nystagmus at maximum deviation, and checking for onset of nystagmus prior to forty-five degrees. The last step of this test is to check for vertical gaze nystagmus. The officer will hold the stimulus in the center and raise the stimulus straight up to maximum elevation to see if nystagmus is present. If vertical gaze nystagmus is present, it is believed to be an indicator of high levels of alcohol or the presence of other drugs.
There are several problems with the Horizontal Gaze Nystagmus test. There are many other causes of nystagmus other than alcohol. If the officer places the driver in a position where the driver has strobe lights, rotating lights, or rapidly moving traffic in close proximity, the driver may have optokinetic nystagmus. Certain drugs like seizure medication, caffeine, and nicotine will cause nystagmus. Nystagmus can result from pathological disorders ranging from brain tumors or brain damage to inner ear problems. Natural nystagmus is fairly common.
The officer who is administering the test has made an initial judgment the driver is under the influence, and the officer is the sole judge of the test results. By starting with the mindset that the driver is under the influence, it is more likely the officer will misread the clues because he is expecting those clues to be present. The clues are compromised if the officer deviates from the standardized procedures.
Walk and Turn Test
The second standardized field sobriety test is a divided attention test called the Walk and Turn test. Initially, the officer will have you assume a heel to toe position by instructing you to place your left foot on a line and place your right foot on the line with the heel of your right foot against the toe of your left foot. You will be told to keep your arms at your side and not to start the test until instructed to do so. The officer is to demonstrate this stance while he is instructing you, the driver, how to stand. After these instructions are given, you will be asked if you understand the instructions so far.
The officer will tell you after he gives the command to start, you are to take nine steps touching heel to toe, after the ninth step, turn, and then take nine heel to toe steps back. The officer is to demonstrate.
The eight clues the officer will be looking for are: failing to keep your balance while listening to instructions, starting the test before instructed to begin, not touching your heel to your toe on every step, stopping while walking to regain balance, stepping off the line, using your arms for balance, making an improper turn, and taking more or fewer than nine steps in either direction.
NHTSA requires a designated straight line and a reasonably dry, hard, level, no slippery surface for the administration of this test. The officer should make sure that there is adequate room for you to take all nine steps. If you are wearing shoes with heels more than two inches high, you should be given the option of removing your shoes. According to the original research, persons with back or leg problems, middle ear problems, as well as persons over the age of 65 have had difficulty performing this test.
The original research indicated that if you have two or more clues on this test or fail to complete the test, you have a 68% chance of having a BAC in excess of 0.10. If you have four or more clues on the Horizontal Gaze Nystagmus test and two or more clues on the Walk and Turn test, there is an 80% chance of having a BAC in excess of 0.10.
Before these percentages are accepted as accurate, you should know the tests were performed in ideal, well lit indoor conditions. The majority of the people tested were over 0.15, making the arrest decision easier and only well trained, experienced officers were used. The deck was stacked and the tests were slanted to yield the result desired rather than a true evaluation of the test validity. By no means was this a scientifically valid study. No one in the scientific community would accept this as a reliable and valid study. However, our government and courts have decided to accept these studies and use these almost exclusively to establish probable cause in DUI cases.
One Leg Stand
The third standardized field sobriety test is the One Leg Stand. This is also a divided attention task requiring you to process verbal instructions while completing physical exercises. The test requires a reasonably dry, hard, level, and non-slippery surface for the administration of the test. The officer will be looking for four different clues. If two or more clues are present or you fail to complete the test, the original research indicates there is a 65% chance you have a blood alcohol level over 0.10.
The officer will start the test by telling you to stand with your hands by your side and your feet together. The officer will then instruct you to begin by raising one leg, either leg, six inches off the ground keeping the foot parallel to the ground. While keeping both of your legs straight and your hands by your side, count out loud one thousand one, one thousand two, one thousand three until told to stop. You will be instructed to begin.
The officer will be looking for four clues. The clues are recorded if you sway while balancing, use your arms for balance, hop to maintain your balance, or put your foot down before being instructed to do so. Similar to the Walk and Turn test, drivers with heels in excess of two inches should be given the option of taking their shoes off. Drivers over the age of 65 will have difficulty with this test. Drivers with back, leg, or middle ear problems will also have difficulty. Another distinction is that drivers who are overweight by 50 or more pounds will have difficulty.
The authors are certified in the administration of the Standardized Field Sobriety Tests. The authors are certified Instructors of the Standardized Field Sobriety Tests and have attended the required refresher courses.
The police officers are taught the procedure to administer the tests in a controlled environment generally as part of their full academy training. It is only a small portion of their training as law enforcement officers and many of the details may be lost in the bulk of material. The manual is very clear that if the officer deviates from the standardized manner, the validity of the test is compromised.
Upon reviewing videotapes of various stops and DUI arrests by the authors, it is very rare to see an officer administer the tests correctly. The officers will almost always testify and record in their police report that they saw all the clues on the tests and that they administered the tests correctly. More than once, though, after reviewing the video, it was determined that these tests were not properly administered. These tests are subjective and biased. They are not reliable and are completely voluntary so you should decline to perform these tests if an officer asks you to do them.
This is why it is important for your attorney to request, preserve, and review any and all video tapes available. Unfortunately, very few agencies in Colorado have in-car or dash cameras. These tests are rarely captured on video. It will be the officer’s subjective opinion on your performance that will be used against you. Although preserving physical evidence seems like common sense, most attorneys do not do this because they think DUI cases are easy. They are easy if all the attorney does is plea the case out without working the case.
In a perfect setting, field sobriety tests may have some validity, but from the authors’ experience, their use in the field by officers is unfair to the drivers. They test normal abilities by having you perform abnormal exercises. The officer giving the test already thinks you are intoxicated--why else would he ask for the test? This officer who basically has his mind made up is the sole judge and interpreter of how you perform the tests. In Colorado, these tests are strictly voluntary. As such, it is the authors’ opinion that a driver should never submit to any form of roadside sobriety testing.