I've posted unendingly in the past about the inaccuracy and unreliability and of breathlayzers in DUI cases. See for example, How Breathalyzers Work (and Why They Don't) and What Makes Breathalyzers Inaccurate? Yet, without these machines — and a public confidence in them — convictions for drunk driving can be difficult for prosecutors to obtain.
Even with the machines, their accuracy relies completely upon (1) the training and honesty of the officer giving the test, and (2) the efficiency and honesty of the forensic crime laboratories calibrating, maintaining and repairing the devices. See, for example, Attorney General Finds Widespread Breathlayzer Inaccuracies: Police Shut Down All Machines and Hundreds of DUI Convictions in Doubt: Inaccurate Breathalyzers.
Bear in mind that mosty states have two different drunk driving charges — and most defendants will be charged with both:
1. Driving under the influence of alcohol (or of drugs, or the combined influence of alcohol and drugs); and
2. Driving with a .08% or greater blood-alcohol level (BAC).
In the first charge, the jury will usually be instructed that if the breathalyzer shows .08% or more BAC, the defendant is presumed to be under the influence — that is, guilty. In the second charge, the jury is instructed that the crime itself consists of the .08% BAC — and that the machine is presumed to be accurate!
In other words, the guilt or innocence of the accused is largely determined in a DUI case by one of these machines: it is, in a real sense, a "trial by machine".
So…how accurate are these machines?
These legal presumptions are rebuttable — that is, the defense attorney can offer evidence to show that the machine in question was not reliable and/or accurate. This may be done through, for example, evidence of contaminated breath samples or videotapes showing incorrect operation by the officer. More commonly, though, it is accomplished through subpoenaing calibration, maintenance and repair records from the government's forensic crime lab to challenge its accuracy.
Problem #1: Very few defense attorneys are skilled and experienced DUI specialists with the necessary technical know-how; and
Problem #2: The records from the crime labs are often inaccurate, incomplete — or fraudulent.
So….how reliable are the crime labs in maintaining, calibrating and keeping accurate records on thse all-important machines?
Federal Review Stalled After Finding Forensic Errors by FBI Lab Unit Spanned Two Decades
Washington, DC. July 29 – Nearly every criminal case reviewed by the FBI and the Justice Department as part of a massive investigation started in 2012 of problems at the FBI lab has included flawed forensic testimony from the agency, government officials said.
The findings troubled the bureau, and it stopped the review of convictions last August. Case reviews resumed this month at the order of the Justice Department, the officials said.
U.S. officials began the inquiry after The Washington Post reported two years ago that flawed forensic evidence involving microscopic hair matches might have led to the convictions of hundreds of potentially innocent people. Most of those defendants never were told of the problems in their cases….
Revelations that the government’s largest post-conviction review of forensic evidence has found widespread problems counter earlier FBI claims that a single rogue examiner was at fault. Instead, they feed a growing debate over how the U.S. justice system addresses systematic weaknesses in past forensic testimony and methods.
“I see this as a tip-of-the-iceberg problem,” said Erin Murphy, a New York University law professor and expert on modern scientific evidence.
“It’s not as though this is one bad apple or even that this is one bad-apple discipline,” she said. “There is a long list of disciplines that have exhibited problems, where if you opened up cases you’d see the same kinds of overstated claims and unfounded statements.”
Worries about the limitations and presentation of scientific evidence are “coming out of the dark shadows of the legal system,” said David H. Kaye, a law professor at Penn State who helped lead a Justice Department-funded study of fingerprint analysis and testimony in 2012. “The question is: What can you do about it?”…
Responding to the FBI review, the accreditation arm of the American Society of Crime Lab Directors last year recommended that labs determine whether they needed to conduct similar reviews, and New York, North Carolina and Texas are doing so….
Again: if you are accused of DUI, the case against you will depend primarily upon the reading of a breathalyzer. And the accuracy and reliability of that machine — which is totally dependent upon a government crime lab's accuracy and efficiency – will be presumed by law!