Breathalyzer devices are not infallible. Neither are Intoxilyzers nor any other portable machine used to administer roadside breath tests to drivers whom police suspect of drunk driving. Such machines have been known to suffer from various calibration and human errors – leading to erroneous results.
Because the machines are fallible, it is fair game to require police to show they have a proper evidentiary basis for such tests when used at trial. In a recent DWI case involving breathalyzer evidence, however, the New York Court of Appeals has held that there are limits to a defendant’s ability to cross-examine documents that bear upon the reliability of breathalyzer devices.
The case concerned a man who was convicted of DWI in New York three years ago. He challenged the conviction under the confrontation clause of the U.S. constitution, which protects the right of criminal defendants to question those who present testimonial evidence against them.
The man argued that under the confrontation clause he should have been allowed to cross-examine the authors of reports on the functionality of the breathalyzer. Those reports were admitted into evidence at the trial. But the man was not allowed to question the technicians who prepared them.
The stakes were high for the man because he already had two drunken driving convictions on his record. He was eventually found guilty of felony DWI and sentenced to prison.
Though the confrontation clause argument was not successful for the defendant, the case does indirectly affirm that portable breath tests are not always accurate. Regardless of whether there is cross-examination of technicians who calibrate the devices, law enforcement must still show that they are in proper working order.
Source: “Breathalyzer documents not subject to Confrontation Clause: Court of Appeals,” Thomson Reuters News & Insight, Daniel Wiessener, 2-19-13