Standardized Field Sobriety Tests (SFSTs)
Field sobriety tests are tests administered by law enforcement to determine if a driver is too impaired to drive. There are three standardized field sobriety tests. They are commonly known as SFSTs. These three—and only these three—have been validated for determining impairment due to alcohol. The three tests are Horizontal Gaze Nystagmus (the “eye test”), Walk and Turn, and One Leg Stand. If an officer attempts any test that is not one of those three, then they’re using something to evaluate impairment that has not been validated to determine impairment due to alcohol.
Horizontal Gaze Nystagmus (HGN) Test
The officer must first evaluate the suspect for any medical conditions that could affect HGN. This involves asking the suspect if he or she has any head injuries or inner ear problems. The officer must check for equal pupil size and resting nystagmus. In addition to determining medical issues that cause nystagmus, unequal pupil size and resting nystagmus can also indicate that drugs could potentially be causing the nystagmus. Then, the officer is going to look for is equal tracking. The officer has to position a stimulus approximately 12”–15” in front of the suspect’s nose, slightly above eye level. A stimulus is typically the tip of the officer’s finger or a pen. The officer has to make one or two passes on each eye to see if both eyes are tracking the stimulus at the same rate. This test has to be performed by moving the stimulus from the center to the outside of the body at the rate of two seconds to reach the maximum distance.
The first HGN clue is lack of smooth pursuit. The officer must make two passes on each eye to see whether the eyes are following the stimulus smoothly. This test has to be performed by moving the stimulus from the center to the outside of the body at the rate of two seconds to reach the maximum distance.
The second HGN clue is distinct and sustained nystagmus at maximum deviation. The officer needs to position the stimulus to where there is no more white showing on the outside of the suspect’s eyes. The officer must hold the stimulus there for four seconds and determine whether there is any jerking at that maximum deviation point. The jerking must be both distinct and sustained.
The final HGN clue is the onset of nystagmus prior to 45 degrees. The officer moves the stimulus slowly from the center towards the outside of the suspect at a rate of four seconds to reach 45 degrees. Once the officer sees nystagmus, they must stop and hold the stimulus there to confirm that the eye is indeed jerking.
After completing all three tests, the officer totals the clues. There is a maximum of six possible clues, with three in each eye.
Something else an officer may do is check for vertical nystagmus. There are no points associated with vertical nystagmus; it is just to determine if there is any intoxication beyond the level detected by the first three HGN tests. The officer will move the stimulus vertically and hold it in position to determine if there is any involuntary vertical jerking of the eyes.
There is a blood alcohol content associated with the three HGN clues. If a suspect exhibits only lack of smooth pursuit, then they have a 0.04 blood alcohol content. A 0.08 BAC is associated with distinct and sustained nystagmus at maximum deviation, and a 0.10 blood alcohol content is associated with onset of nystagmus prior to 45 degrees. These tests are cumulative. This means that the onstet of nystagmus prior to 45 degrees can’t exist without both lack of smooth pursuit and distinct and sustained nystagmus at maximum deviation existing.
Walk And Turn Test
The Walk and Turn is a divided attention test. This test has two phases. They are the instructional phase and the walking phase. Before the instructional phase, the officer must medically clear the individual. It is a fatal error in the administration of the test if the officer fails to do this. The officer must designate a line and tell the suspect to place their left foot on the line with their right foot in front of it touching heel to toe. The officer must demonstrate the stance. The suspect will then be told to maintain his position and not to start until told to do so. Finally, the officer is supposed to ask the suspect if they understand.
The suspect has to maintain his or her position while the officer demonstrates the walk-and-turn.The suspect must take nine heel-to-toe steps down the line, turn and take nine heel-to-toe steps back. The officer has to demonstrate three heel-to-toe steps and the turn. During the turn, the suspect must leave their front foot on the line and take a series of small steps. While walking, the suspect must watch their feet, keep their arms at their sides, count out loud, and not stop walking until they are told that the test is complete. At the end of all of the instructions, the officer must ask the suspect again if they understand.
There are eight clues of intoxication associated with the Walk and Turn. There are two in the instructional phase and six in the walking phase. The two in the instructional phase are inability to maintain balance and starting too soon. The six clues in the walking stage are as follows: stops while walking, does not touch heel to toe, steps off line, raises arms for balance, turns improperly or loses balance while turning, and takes the wrong number of steps. If a suspect takes a step that is more than half an inch away from the toe of the other foot, then that is considered a clue for the Walk and Turn.
The suspect may raise one or both arms to exhibit the “raises arms for balance” clue. The arm(s) must be raised more than 6” to qualify as a clue. The arms must be raised for balance. If somebody raises their arms to brush their hair out of their face or to scratch something, then that does not constitute raising arms for balance.
One Leg Stand Test
The One Leg Stand test is a divided attention test. This test has two phases. They are the instructional phase and the walking phase. The officer looks for four clues of intoxication. These are: puts foot down, raises arms for balance, sways, and hops. The officer has to first medically clear the suspect. During the instruction phase, the officer must tell the suspect to stand with their feet together and to place their arms at their sides. The officer must demonstrate this stance and tell the suspect not to start until instructed. At the end of the instruction phase, the officer must ask the suspect if they understand. While the suspect is in that position, the officer must tell them to begin only when they are told to do so and once they begin to raise one foot approximately six inches off the ground. The officer has to demonstrate raising one foot off the ground. The suspect may raise whichever foot they want.
The officer must tell the suspect to keep their raised foot parallel to the ground, keep both legs straight, keep both arms at their sides, look at the elevated foot, and count out loud in this manner: “One thousand one, one thousand two, one thousand three.” The suspect is to continue counting in that manner until told to stop. At the end, the officer must ask the suspect if he or she understands.
The suspect must raise both arms to exhibit the “raises arms for balance” clue. The arms must be raised more than 6” to qualify as a clue. The arms must be raised for balance. If somebody raises their arms to brush their hair out of their face or to scratch something, then that does not constitute raising arms for balance.
SFST Frequently Asked Questions
Can I Contact An Attorney to Decide Whether to Perform the SFTS?
A driver does not have the right to contact an attorney when deciding whether to perform the field sobriety tests. Taking the tests is a judgement call. Only you know how much you had to drink and how high your alcohol tolerance is. Try to make the best decision possible considering your alcohol consumption, your tolerance to alcohol, and the implications of refusing the tests.
Can I Refuse to do the SFSTs?
You can absolutely refuse to do the field sobriety tests. Officers are very sneaky in how they attempt to get someone to take the tests. They won’t tell you that the tests are optional. What they will do is say something like, “What I’d like you to do right now is look at the tip of my pen with your eyes,” and then they will continue with the other instructions for the horizontal gaze nystagmus test. Alternatively, they may say something to the effect of, “I’d like you to do some tests now so that I can determine if you are able to drive.” Then continue with the administration of the tests.
You are well within your rights to tell the officer that you do not want to perform these tests. You may also stop taking the tests at any time. Just remember that if you perform these tests and you do poorly on them, then that is evidence that will be used against you. If you refuse to perform the tests, then law enforcement will not be able to use poor test results against you. However, if the case goes to trial, then the jury can make assumptions as to why you chose not to perform the tests.
If you are heavily intoxicated and you know that you are heavily intoxicated, then it may not be to your benefit to perform these tests. If you look bad on the video, then that video will have to be overcome somehow. If you are not intoxicated and you know that you are not intoxicated, then it may be to your benefit to perform the tests. However, officers very frequently administer the tests improperly. Improper administration of the test can lead someone to perform the tests poorly.
What Happens if I Refuse the SFSTs?
People rarely refuse to perform the field sobriety tests. If the suspect refuses to perform the field sobriety tests, then the officer must have some other reason to arrest that person besides poor performance on a field sobriety test. The officer must find other things that indicate intoxication. Examples of this could be the poor driving that the officer observed, an odor of alcohol emanating from the suspect’s breath, bloodshot eyes, or slurred speech. Ultimately, the officer must have probable cause to arrest somebody.
Do Standardized Field Sobriety Tests Really Determine Impairment?
The standardized field sobriety tests have been validated to determine impairment on alcohol; they have not been validated for impairment on anything else. However, they are not 100% correct. Sometimes a person who is impaired may be able to perform the SFSTs well, and the officers will not detect impairment. Alternatively, sometimes a person who is not impaired will not perform the SFSTs well, and the officer will incorrectly determine that they are impaired. The most recent studies show a high percentage of correct evaluations by the officer when the tests are administered correctly. The key is that the tests must be administered correctly.
A person’s performance on the walk and turn and one leg stand tests can be good if that person has developed a tolerance to alcohol (i.e. they’re an alcoholic). The only test that a person cannot do better on due to alcohol tolerance is Horizontal Gaze Nystagmus. This is because the jerking of the eyes is involuntary. HGN is the most reliable of the three tests.
I have never seen an officer administer any test 100% correctly. Some of the errors are major and some are minor. The bigger the error, the easier it is to show that the results are invalid. Their training states that if the administration of the tests is incorrect, then the results of the test can be invalidated.
What Can Affect SFST Performance?
A variety of things can affect the results of the SFSTs. The officer is supposed to ask the suspect if they have any medical conditions that could affect their performance on any of the tests prior to administering them. Drugs, health issues, physical injuries, age, weight, and footwear can affect how someone does on an SFST.
Some drugs and health issues can affect HGN. Dissociative anesthetics, such as PCP, can cause resting nystagmus, which is the jerking of the eyes as they look straight ahead. Nystagmus can also be caused by certain pathological disorders, including brain tumors, brain damage, and some diseases of the inner ear.
For the One Leg Stand and the Walk and Turn, the officer is specifically supposed to ask the suspect if he or she has any leg or knee injuries that could affect their ability to stand, walk, or balance. Some studies suggested that individuals over 65 years old or people with back, leg, or inner ear problems have difficulty performing the Walk and Turn and One Leg Stand.
The 1984 SFST student manual stated that individuals who are 50 pounds or more overweight would have difficulty performing the Walk and Turn and One Leg Stand. The other thing that can impact an individual’s ability to perform the one-leg stand and walk-and-turn is wearing heels more than 2” high or other unusual footwear, such as flip flops. The officer is supposed to ask anyone wearing that type of footwear if they would like to remove their footwear.
Are Standardized Field Sobriety Tests Admissible in Oklahoma Courts?
SFSTs are admissible in Oklahoma courts, but officers never administer the tests correctly. I’m always able to find something wrong with how the tests were administered. Through the training that I’ve attended, I’ve developed a checklist of over 150 items for DUI arrests. I use that checklist to evaluate the way the tests were administered and whether there were any other potential indicators of intoxication.
Since I always find something wrong with the administration of the tests, I have absolutely no problem putting that information in front of a jury. If there is a video of the test being administered, then I absolutely want it. Somebody looking at a video of a person failing a test might not necessarily be a bad thing because the officer may have done a very poor job of giving the instructions and administering the test.
Are Field Sobriety Tests Always Recorded?
The tests are not always recorded. It’s helpful if there’s video because officers usually administer them incorrectly. It’s very difficult to tell whether the officer administered the test correctly if there is no video. This is why I do everything I can to get the video of the stop and administration of the tests. Sometimes we just get the bodycam, sometimes we just get the dashcam, and sometimes we get both. Of course, it’s best to have both because it gives a great perspective of everything that occurred. What you may not be able to see on the bodycam, you may see on the dashcam and vice versa.
Even with video, it’s most challenging to determine whether the Horizontal Gaze Nystagmus was administered correctly because the officer is supposed to move the stimulus in a certain direction at a certain rate. There is no way to tell whether that was done if there is no video. If it’s only recorded on a bodycam, then it can be very difficult to see what’s going on because the stimulus and/or eyes are often out of view of the camera. So, that’s why we try to get as many angles and videos as possible. Sometimes we can get video from other officers or other patrol cars. Their own training says that if they didn’t put something in the report, then it didn’t happen. If it’s not on video and not in the report, then it didn’t happen. If there’s no video and it’s not in the report, then it still didn’t happen.
Factors That Could Exempt a Driver From Having to Perform the Field Sobriety Tests
There are some things that can exempt a driver from having to perform field sobriety tests. For example, if somebody is in a wheelchair, then there would be no way for them to perform the Walk and Turn and One Leg Stand. With regards to Horizontal Gaze Nystagmus, some things can change the ability to fully test the individual. These things include being blind in one eye or having a glass eye. If that’s the case, then the maximum number of clues that could be observed would be three because the officer would only be able to see three clues in the functional eye.
If the suspect states that they have a leg, knee, or ankle problem prior to performing the One Leg Stand or Walk and Turn, then the officer will likely ask the suspect to perform the tests anyway. The officer will then say that they took those injuries into consideration when evaluating the person for intoxication.
SFST Defense Strategies
The biggest defense strategy is that the test was administered incorrectly. The NHTSA SFST instructor training manual states that the entire test may be invalidated if it is administered incorrectly. There are numerous errors that the officer can commit if they administer the tests incorrectly. Some of these errors are fatal, and others are clue-specific errors. A fatal error has the highest chance of invalidating the entire test. For instance, failing to medically clear somebody is a fatal error on the Walk and Turn. If the officer doesn’t ask the suspect if he or she has any leg, ankle, knee, or inner ear injury prior to the suspect performing the test, then the entire test may be invalid. If the suspect has any of those medical conditions, then that would likely result in their performing the test poorly.
Other strategies include looking at the area where the test was administered. For example, the Walk and Turn has to be done on a relatively smooth and level area. Sometimes, these officers have the suspect perform the test in the grass or on a sloped driveway. Things like that can invalidate a test.
A frequent error on the HGN is the officer moving the stimulus too fast. If it’s moved too fast, then HGN can actually be induced. Frequently, officers don’t hold the stimulus at maximum deviation for four seconds when looking for distinct and sustained nystagmus at maximum deviation.
Sometimes, officers have not been trained to administer the tests they’re administering. Most officers are SFST trained. About half of the officers are ARIDE trained. Some ARIDE-trained officers think they’re Drug Recognition Experts (DREs). There are some tests that only DREs are allowed to administer, but ARIDE officers frequently try to administer those despite not having been properly trained on them. And, some officers that have gone through only SFST training will attempt to administer tests that only ARIDE-trained officers are qualified to administer. If an officer has not been properly trained on how to administer the tests, then it’s highly likely that they aren’t administering them correctly and the entire test should be thrown out.