The Philadelphia Police Department recently admitted that four of the Breathalyzer machines regularly used by the department to test drivers' blood alcohol levels were improperly calibrated for several months.

According to a police department spokesman, more than 1,100 DUI cases will be affected by this error. Convicted defendants who may have been tested with improperly calibrated machines are being notified by the county district attorney's office, and will likely be permitted a DUI retrial. The spokesman announced that the improper calibration calls into question more than 10 percent of the city's DUI arrests from 2009 to 2010.

Authorities involved in the case originally thought that only one machine caused the discrepancy. However, an investigation revealed that half of the department's machines had not been calibrated correctly. A department spokesman confirmed that the officer believed to be responsible for the improper calibration has been reassigned, and that all of the department's Breathalyzer machines have been recalibrated.

The faulty machines have raised many questions from Pennsylvania DUI defense attorneys who believe that many innocent drivers may have been wrongly punished for DUI offenses, and have been sentenced to jail time or have lost their driver's license as a result. There is also concern that offenders may have been charged too severely as a result of inaccurate evidence provided by the Breathalyzer machines. These unnecessarily severe or false charges could lead to an influx of lawsuits filed against the city by wrongfully convicted defendants.

In the alternative, safety advocates have raised concerns that offering all convicted of DUI during the Breathalyzer malfunctions may allow guilty drivers to avoid DUI charges.

Source: Philadelphia Daily News, "City fails breathalyzer test in 1,400 cases", Dana DiFilippo, 24 March 2011