Is it possible to challenge the reliability of Breathalyzer test results?
A. Yes, though this is usually a complicated and difficult process. The use of a breath test is by far the most popular scientific method for establishing that drunk driving has occurred. Some defendants, however, have been able to challenge the results of such tests in court, thereby preventing a conviction. Breathalyzer evidence may be attacked on a number of grounds, including lack of certification and/or incompetence of the tester, lack of certification and/or accuracy of the machine, failure to follow proper maintenance/cleaning/testing procedures of the machine, etc. The investigation to determine whether there might a basis for attacking the test almost always occurs in the pretrial stage of the case by use of discovery and motion practice. It is also recommended in some instances to retain an expert witness, usually a scientist and at significant expense, to testify as to the scientific methodology and flaws of the test as it specifically applies to the particular defendant and
