Until 1992, The State of Tennessee had to present expert testimony as the the results of a breath alcohol test in a Tennessee DUI case.  In State of Tennessee v. Sensing 843 S.W. 2d. 412 ( Tenn.1992), The Tennessee Supreme Court relaxed the admissibility requirements of a breath test machine.  Instead of requiring expert testimony, the court established strict rules for the breath alcohol test.  One of those rules is the observation period prior to giving the test.

In Tennessee, as with most states, when a breath test is requested a defendant must remain under observation of a law enforcement officer for a twenty minute period.  The purpose is to ensure that the subject has not burped, belched, hiccuped, or placed anything into the mouth.  The rule is designed to ensure a false breath test is not created though mouth alcohol.

Thus the starting point in defending a drunk driving case with a breath test is to question the 20 minute observation period.  The courts have held that doing paper work during the observation period invalidates the breath test.

  1. Was the police officer watching you the whole time?
  2. Was the police officer doing paperwork while he was watching you?
  3. Was the Police officer talking on his cell phone or radio?

Right now, I have a case where the police officer was talking to my client’s wife on the cell phone during the observation period.  Remember the tests must be done according to protocol to be admissible.