A DWI attorney in Pennsylvania recently challenged the value of breath test evidence for DWI cases in the State of Pennsylvania in Commonwealth v. Schildt. The judge hearing the case ruled that no breath test result below a 0.05% or above a 0.15% was valid given the testing procedures for Pennsylvania. There are several important issues that arise from this ruling for DWI cases in the St. Louis area and for Missouri cases in general. First, the breath testing program in Pennsylvania is more sophisticated, and includes better safeguards against error than the testing system currently used in Missouri. Sadly, in a Missouri DWI case only one breath sample is required from the suspect. As many as 45 other states, including Pennsylvania require duplicate testing. In states that use duplicate testing a suspect blows into the breath test, waits 10 or so minutes then takes a second breath test. The two breath test samples are then compared to ensure they are within a relevant range. If the two tests are not within the relevant range, then both samples must be thrown out because there is no way of knowing which sample was contaminated or inaccurate. Unfortunately, Missouri does not utilize this most basic fail safe against erroneous breath test results.
In a Missouri DWI case the breath test machine is required to be calibrated every 35 days. The breath test machines are calibrated only with a solution that should yield a result either 0.04% or 0.10% depending on the solution used. Most breath test machines in St. Louis DWI cases are calibrated with the 0.10% solution. Once again, there are deficiencies in this system when compared to the Pennsylvania breath testing system which tests three different alcohol level solutions during each calibration. It should be a bright red flag to all experienced DWI lawyers in Missouri that a breath testing system much more advanced than our own has been held inaccurate for evidentiary value.
The lesson that must be taken from the excellent work of Justin McShane in Pennsylvania is that breath test results are not an unimpeachable fact. Breath tests results in DWI cases must be challenged, especially in a state like Missouri where there are very minimal standards for administering a breath test. With all of the legal and financial penalties that people have riding on a possible DWI conviction, it is more important than ever that experienced DWI attorneys analyze and fight not only the results of individual breath tests but the Missouri breath testing system as a whole. The State of Missouri can continue to advocate a tough on DWI approach, but that approach will ring hollow as long as there is a scientifically unacceptable breath testing system in the state.