Thousands of citizens are convicted every day of driving with a blood-alcohol level of .08% — based entirely upon the readings of these machines.  In a "trial by machine", the results of these devices legally establish a rebuttable presumption of guilt and are considered proof beyond a reasonable doubt.  See Whatever Happened to the Presumption of Innocence? and Trial by Machine. 

Philadelphia, PA.  March 25 — A day after Philadelphia police announced that miscalibrated breathalyzers had compromised 1,147 drunken-driving cases, District Attorney Seth Williams  declared he would conduct a wholesale review of all DUI cases during the 15 months in question.

Philadelphia police file 8,000 to 10,000 drunken-driving cases each year, so the review announced Thursday by Williams’ office will involve a staggering amount of work that will take months to complete. 

Deputy District Attorney Edward McCann, chief of the Criminal Division, decided to launch the review, said Williams’ spokeswoman, Tasha Jamerson. Assistant District Attorney Lynn Nichols will lead a team of prosecutors and staff that will examine the cases from September 2009 to November 2010.

Besides the cost of reviewing thousands of DUI prosecutions and likely retrying some, the police and city could face civil lawsuits by people wrongly convicted – some of whom may have lost their driver’s license, their job, or their freedom.