5 attacks that can be used on DUI field sobriety tests

Last Modified: August 10, 2023

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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