Absent a breath or blood test, the Commonwealth will likely place great weight on the defendant’s performance on standardized field sobriety tests. Field sobriety tests are divided-attention tests that are designed to test the operator’s condition and ability to do multiple tasks at once. Typically, the police officer conducts three of the following tests:
- Horizontal Gaze Nystagmus,
- nine-step heel-to-toe and turn,
- walking a straight line,
- standing on one foot and counting,
- reciting the alphabet, or
- touching a finger to the nose.
The officer not only gives the test but ultimately decides whether the subject passes or fails.
If the Commonwealth intends to present evidence of a “failed” field sobriety test, I am prepared to challenge the scientific underpinnings (or lack thereof) of these so-called tests. While the officer will likely be allowed to describe the balancing exercises that he had the accused perform, he should not be allowed to testify about the correlation between blood alcohol concentration and the accused’s performance. The government cannot and will not establish that field sobriety tests have been peer reviewed and accepted by the scientific community (as opposed to accepted by law enforcement community). As such the officer should not be even permitted to refer to any Field Sobriety Tests as “tests” and should be required to call them “coordination exercises” or something similar. He also should not be permitted to refer to “standardized clues” when describing the accused’s performance as indications of intoxication. Most importantly he should not be permitted to give an opinion that the accused “failed.” The officer will be permitted to give a layman’s opinion on the appearance of intoxication but he should not be allowed to bolster his opinion with scientific-sounding support for his opinion. He also should not be described by the prosecutor as having specialized knowledge about impairment since whether the driver was impaired is for the jury to decide.