In most drunk driving cases, by far the most important evidence comes from a breath test. Our DUI laws even provide that they are sufficient by themselves to warrant a conviction. The accuracy of these devices is, therefore, critical. And I’ve posted dozens of time on the inaccuracy and unreliability of breathalyzers. See, for example, How Breathalyzers Work — and Why They Don’t, Attorney General Finds Widespread Breathalyzer Inaccuracies: Police Shut Down All Machines and More Massive Breathalyzer Failures.
Besides the inherent inaccuracies of breath-testing devices, they are also entirely dependent upon proper maintenance and calibration by the police making the arrest. Failure to properly calibrate one of these devices on a regular basis is going to result in false readings — and wrongful convictions.
Unfortunately, cops and police agencies are notoriously lazy or incompetent when it comes to these irritating "technical" tasks….
SFPD Breathalyzer Error Puts Hundreds of DUI Convictions in Doubt
San Francisco, CA. March 5 – Hundreds, or even thousands, of drunk driving convictions could be overturned because the San Francisco Police Department has not tested its breathalyzers, officials said Monday.
For at least six years, the police officers in charge of testing the 20 breathalyzers used by the Police Department did not carry out any tests on the equipment.
Officers instead filled the test forms with numbers that matched the control sample, said Public Defender Jeff Adachi, throwing countless DUI convictions into doubt.
“We do expect that the cases will be in the hundreds. It’s possible that it could go into the thousands. The District Attorney’s Office is still investigating the scope of this,” Adachi said during a joint news conference with District Attorney George Gascon…
Amazing….no calibration tests in six years! The cops just made up numbers to make the machines look accurate.
Even more amazing that a reading from one of these machines is legally considered proof beyond a reasonable doubt in a DUI case — and even triggers a legal presumption of guilt, forcing an accused citizen to prove his innocence. See Whatever Happened to the Presumption of Innocence? and How to Overcome Scientific Facts: Pass a Law.
(Thanks to Andre Campos and Murphy Mack.)