Motorists in Pennsylvania and around the country who are charged with driving under the influence are usually taken into custody after breath tests reveal their blood alcohol concentrations to be .08% or higher, but questions have been raised about the reliability of toxicology evidence in drunk driving cases for years. A team of reporters from the New York Times recently investigated the way police departments in the United States conduct breath tests, and they found that most of the equipment used is extremely unreliable.
The results of the investigation were released on Nov. 3, and they reveal that virtually all law enforcement agencies use breath-testing equipment that has been poorly maintained. Accurate results are only produced when these devices are regularly recalibrated and filled with the correct chemical solutions. The report suggests that these requirements are widely overlooked. Reporters discovered one machine that was being used as a nesting site by rats and another that had been drilled by police officers to influence the results it produced.
The result of this lax oversight has been the exclusion of tens of thousands of breath tests. Criminal cases must be proved beyond reasonable doubt, which means that judges throw out drunk driving charges when the toxicology test results supporting them are determined to be unreliable even when circumstantial evidence suggests that defendants were highly intoxicated. More than 36,000 breath tests were ruled inadmissible in Massachusetts recently in what has been described as the nation's largest ever exclusion of forensically obtained evidence.
The kind of shortcomings uncovered by this investigation will likely be well known to experienced criminal defense attorneys. When defending clients accused of driving under the influence, attorneys may check maintenance records to assess the validity of toxicology evidence. If these records reveal that oversight was lax and maintenance was substandard, attorneys could seek to have DUI charges dismissed.