Field tests are less reliable than chemical tests
The best indicator of possible driving impairment appears to be a reliable blood alcohol test. Chemical tests can objectively and accurately determine the blood alcohol concentration (BAC) of the driver within the margin of error of the testing method and instrument. From this analysis, an opinion can be given on driving impairment based on scientific studies.
Field sobriety (non-chemical) tests are less reliable, and often are a poor indicator of driving impairment or sobriety. One of the reasons for this is the inherent error in subjective evaluations of an individual whose normal performance is unknown.
Nevertheless, field sobriety tests are still used as a tool to:
- Enable an officer to develop probable cause for the stop or arrest.
- Assist in establishing possible physical or mental impairment at a time close to driving.
- Establish the general causal relationship between alcohol and driving behavior.
Types of tests
A wide variety of field sobriety tests have been used, including:
- Asking distracting/interrupting questions.
- Finger to nose.
- Finger count test.
- Reciting or writing the alphabet, with signature and time and date.
- Counting backwards from 100.
- Tracing (a paper-and-pencil exercise).
- Romberg balance test.
- Romberg balance test combined with finger to nose.
- Nystagmus (“HGN”).
- One leg stand.
- Line walk.
- Hand pat.
- Picking up coins.
- Recitation of date and time.
- Standing heel to toe.
Standardized and non-standardized tests
The United States Department of Transportation, National Highway Traffic Safety Administration (NHTSA) studied several field sobriety tests starting in 1975, with the results being published in 1977.
Three field sobriety tests were determined to have a good correlation with impairment when used together (provided that they are administered in strict compliance with the testing protocols). The three tests have come to be referred to as Standardized Field Sobriety Tests or SFSTs. The three SFSTs the research validated were:
- Horizontal gaze nystagmus.
- Walk and turn.
- One leg stand.
Other tests are not standardized, but are still commonly used by many officers. These tests include:
- Romberg balancing test.
- Finger to nose test.
- Alphabet, count-down, and finger count tests.
- Handwriting.
- Hand pay and picking up coins.
Finger to nose
The finger to nose test, which is administered in a variety of formats, generally requires the subject to close their eyes and then touch the tip of their nose with the tip of their index finger, alternating hands.
The National Highway Traffic Safety Administration research project revealed that the finger to nose test (along with the Romberg test) only reflects the presence of alcohol, and does “not increase the predictive ability of testing.”
Alphabet, count down, and finger count tests
The alphabet test requires the subject to recite part of the alphabet (e.g., starting at a letter other than A and stopping at a letter other than Z). Alternatively the entire alphabet is required to be recited or written down. Contrary to urban legend, the alphabet test does not require the subject to recite the alphabet backwards.
The count down test requires the subject to count aloud numbers in reverse. For example count backwards from 90 to 70.
Sometimes the officer will have the subject stand with one foot in front of the other in a heel to toe position when performing the alphabet test or the count down test.
The finger count test requires the subject to touch the tip of the thumb to the tip of each finger on the same hand in a particular order while counting (e.g., “one, two, three, four—four, three, two, one).
Handwriting
A research study has concluded that handwriting changes can be observed at any level of alcohol. However, “none of the alterations in handwriting can be attributed to the effects of alcohol intake alone.”
However, not all studies indicate that handwriting may be a reliable indication of alcohol concentration. In one study, deterioration in handwriting was charted for 35 men and women who had provided handwriting samples prior to the consumption of alcohol, and again after the drinking period had ended. The researchers concluded that handwriting could not be used in any way to measure accurately the blood alcohol concentration of a writer.
Hand pat and picking up coins
The hand pat has the person taking the test place one hand palm up and in front. The other hand is placed on this hand with the palm down. The top hand then pats the bottom hand once and is then rotated 180 degrees to pat the bottom hand with the back of the top hand. The test continues until the officer tells the subject to stop. The subject is told to increase the speed of the rotation of the hand during the test.
Some consider the test to be a failure-designed test because as the speed increases most people will eventually double pat or roll or chop their hand instead of patting the hand one time cleanly on each rotation as the test requires.
Like the hand pat, picking up coins also involves the use of the hands rather than balancing on a person’s legs. This has the advantage of not having to use the legs when a subject tells the officer during the pre-field sobriety test questioning that he or she has a bad back, leg or knee. Like the hand pat, the test suffers from not having been scientifically validated as an accurate prediction of sobriety. The test has the subject pick up with one hand several coins on a flat surface like the hood of the car. It is rarely used.
Not all tests have been studied
Some of the tests have been explored for their degree of reliability. For example, there is considerable data on the nystagmus (HGN) test and the Romberg test, since these tests have clinical origins.
However, not all of the various field exercises have been studied for reliability, or have been validated as meaningful indicators of alcohol impairment. Some tests are used even without proper validation or any scientific study to support their use by officers. Some tests merely look for changes in divided attention ability.
5 attacks that can be used on DUI field sobriety tests
Using the cross-contamination dynamic
When your attorney cross-exams the arresting officer in your trial you may notice that an attack about one test can cross-contaminate the other tests.
That is, your attorney may make a point once with regard to a specific field sobriety test, and then not mention that it also applies to another field sobriety test. Instead, your attorney may let the jurors figure out for themselves that the same problem would affect the other tests. This allows the cross-examination to germinate on its own. Sometimes if the defense attorney makes the same argument with each different field sobriety test it dulls the cross-examination and gives the appearance that there are no other points to make.
The 5 cross-contamination attacks
1. The testing area is sloped.
Whether the particular test is the walk the line test, the Romberg test, or the one leg stand, it should be administered on a level surface. This is rarely the case because there is almost always a little gradient.
Sometimes the testing area actually slopes in two different directions.
Obviously, if the area was not level during the Romberg test, it did not suddenly become level during the one leg stand.
2. Lack of a baseline.
If the officer does not know how you would have performed on the field sobriety tests without the consumption of alcohol, a claim cannot validly then be made that poor performance was due to alcohol impairment.
Perhaps you are not particularly coordinated. You may have also been tired, or had some other reason (other than alcohol) for poor performance on a test.
3. The officer does not know the why of the test.
The prosecutor will tout the arresting officer’s knowledge, experience and training in administering and evaluating field sobriety tests because the state offers the police officer as an expert.
Your attorney may challenge this expertise by asking the officer why the test is administered in a certain manner. For example, few officers know the reasons why the head is tilted back and the eyes are closed in the Romberg test. For this reason the Romberg test is good place to use this cross-contamination dynamic.
4. Innocent reasons for poor performance.
Field sobriety tests are not easy for everyone. Fatigue, lack of coordination and stress are just of few of the many reasons to explain why someone did not perform well.
Your attorney may find that the horizontal gaze nystagmus test is a good time to introduce the notion that there are many reasons why you did not perform perfectly. The reason for this is that the horizontal gaze nystagmus test has a bevy of innocent reasons to explain a claim of failure on the test.
5. Complex instructions are given in a short period of time.
Most field sobriety tests have numerous requirements. Despite the complexity of many of the instructions, the tests are often explained and demonstrated only once, and in as little as ten to fifteen seconds. You are then expected to have an instant retention of the instructions. Rather than a test, this process takes on the onus of a “pop quiz.”
Your attorney might time how long the officer takes to give the instructions when the officer testifies about the instructions on direct examination. Then on cross-examination your attorney can ask the officer if the officer gave the instructions to you in the same manner as the officer just testified in court. The answer will probably be yes. Then your attorney might have the officer confirm that the instruction phase took all of fifteen seconds.
Then, in closing argument, your attorney might remind the jury how well you did on the field sobriety tests despite the brevity in which the complex instructions were given. Your attorney might ask the jurors if they themselves can recall the exact instructions of all the field sobriety tests. Furthermore, your attorney might remind the jurors that they have had the benefit of hours, not seconds, of time being spent in court discussing the field sobriety tests.
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