Test Anxiety

Posted on in Criminal Law

sobrietyThe breath or blood chemical test is usually the primary evidence in a DUI prosecution. But if such evidence is unavailable, typically because the accused exercised his or her right to refuse to provide a sample, the prosecution must normally rely on field tests.

Under the theory that "more is better," many officers employ a wide range of tests: reciting a portion of the alphabet, counting backwards from one number to another one, and even trick questions like "what was the year of your second birthday?"

However, there are only three field tests that are approved by the National Highway Safety Administration for use in these situations. And, each one is flawed in its own way.

Horizontal Gaze Nystagmus

This test, which has been around since the 1970s, measures involuntary muscle movements in the eye. Typically, subjects are asked to follow a specific point with their eyes, like the tip of a pin or flashlight bulb, without moving their heads. If there are four or more "clues" between the two eyes, there is about a 77 percent chance that the subject is intoxicated.

This test has come under fire recently. In fact, the Illinois Supreme Court sharply limited this test, ruling that it is admissible to show that, more likely than not, the defendant had consumed alcohol. It does not constitute proof of intoxication beyond a reasonable doubt.

Furthermore, the 77 percent figure assumes the test is conducted in controlled conditions. Field tests are just that: exams that are conducted in the field under uncontrolled conditions.

Walk and Turn

In the tried and true "walk a straight line" test, the subject must take nine steps heel to toe, turn around, and do the same thing. During the test, the officer is looking for clues like:

  • Losing balance while listening to instructions;
  • Beginning the test before instructions are complete;
  • Starting on the wrong foot;
  • Stopping to regain balance;
  • Using arms to maintain balance; and
  • Walking the incorrect number of steps.

If the officer sees at least two clues, there is a 68 percent chance the person is intoxicated.

Once again, the conditions vary greatly. For example, many suspects must walk an imaginary line in the dark. Evidence of uncontrolled conditions make this rather questionable test even more unreliable.

One Leg Stand

This test is similar to the walk and turn in many respects. If the officer sees at least two clues, there is a two in three chance the subject is intoxicated. The test also suffers from the same deficiencies and unreliabilities as the walk and turn, and an aggressive attorney can exploit them all at trial.

If you were arrested for DUI, contact an experienced criminal defense attorney in Arlington Heights today. Call Scott F. Anderson at 847-253-3400.