I’ve written repeatedly in the past about the inherent inaccuracy and unreliability of breath testing machines (generically referred to as "breathalyzers"). See, for example, How Breathalyzers Work — and Why They Don’t, What Makes Breathalyzers Inaccurate? and Ohio Rejects Popular Breathalyzer: Accuracy Challenged. And see a treatment of the issue on my law firm’s website, Breathalyzer Accuracy.
Independent of the inherent problems in the machines and the variations of human physiology involved, a further issue has always been the reliability of the governmental crime laboratories responsible for the calibration and maintenance of the machines. See my posts, Lab Fraud Discovered in Breathalyzer Accuracy Checks, How to Prove Breathalyzer Accuracy: Falsify the Records and Houston Grand Jury Subpoenas DAs in Breathalyzer Cover-Up.
As an example, consider the following recent ABC-TV news story:
Forensic Failures at State Crime Labs May Jeopardize Cases
Chicago, IL. Sept. 23 – Some drunk drivers could go free because of law and disorder at Illinois State Police crime labs.
The ABC7 I-Team uncovered a pattern of forensic failures that could put criminal cases in jeopardy and risk thousands of charges and convictions being thrown out.
Unreliability in science is like a bull in a china shop: it can wreck everything. The Illinois state crime lab is under fire by a criminal defendant who may have been wrongly charged- using evidence with inaccurate or unreliable test results – and under fire by defense attorneys and experts alarmed by what they see as shoddy science.
James Kisla struck a pedestrian on Yackly Avenue in Lisle. According to court records, a couple ran across the middle of a street, into traffic, in front of Kisla’s car.
Kisla wasn’t ticketed in the 2011 accident but a sobriety test had him just beyond the legal limit. Then Kisla’s lawyer discovered this – a 2011 internal audit of the Illinois State Police Laboratories and blood alcohol test inaccuracies.
State police officials tell the I-Team their tests results were accurate. But the audit called for corrective action – a revision of the labs’ "scientific method" and ordered "in-service training for the state police toxicology section."
Kisla’s lawyer, Don Ramsell, showed the audit to prosecutors. "The prosecutor decided not to even bring the blood test results into evidence. It only took one day after for the judge to declare Mr. Kisla innocent of all the charges," Ramsell said.
Up to 15 years in jail – but Kisla was cleared because the state police forensic tests were unreliable…
The I-Team found more lab mistakes occurring in the state’s labs. We examined these internal Illinois State Police lab audits and reports going back to 2003 and found numerous blood and urine testing errors. "Test samples (were) switched," there were "mislabeled specimens", a "mix up of results," "improper calibrations" of tests, "improper methods (were) used," and "samples wrongly destroyed."
But Ramsell says the biggest problem is none of the state’s lab results for blood and alcohol tests can be considered reliable. That is because their lab technicians have never performed "method validations" on their testing procedures – a fundamental check and balance in the science world.
"Not only is it completely unacceptable but it’s shocking that no one from the state police ever reported that to anybody," Ramsell said…
Yet the readings from these unreliable machines are automatically assumed by law to be reliable and admissible in evidence — unless the defendant can somehow prove they aren’t. And once admitted in evidence, the jury in most states is given jury instruction stating that if the reading is over .08%, the defendant is rebuttably presumed by law to be guilty. See my post, Whatever Happened to the Presumption of Innocence?.