Last week's blog post looked at the efficacy of private breathalyzers for personal use. While those devices may give Wisconsin drivers a chance to assess their sobriety before driving, the results of a self-administered test will not be factored into an officer's decision to arrest a person for allegedly driving drunk. A variety of tests can be used to determine a driver's level of intoxication and those blood alcohol tests can be run on a driver's hair, breath, blood, urine or saliva.
Breath and blood tests are most commonly used for determining a driver's blood alcohol content or BAC. While breathalyzer antidotes such as mouthwash and mints generally will not positively impact a driver's breathalyzer result, maintenance performed on an alcohol-testing machine can directly play into whether a driver's reading is accurate.
In particular, breathalyzers should be regularly tested to ensure that they are providing correct readings. This testing is called calibration and is done to safeguard against making faulty readings against individuals whose BAC does not rise above the statutory limit. An improperly calibrated breathalyzer can provide a false-positive against a sober driver and result in that individual facing a drunk-driving related charge.
While calibration can be a problem for breath tests, laboratory issues can be problems for the results of blood or urine tests. Contaminated or swapped samples can result in an innocent driver being confused with an intoxicated one and facing crimes related to impaired driving. Human error can be a major issue for laboratories that handle drunk driving tests.
The results of a blood alcohol concentration test may seem definitive but can always be analyzed to ensure they are accurate. Individuals who believe that their testing may have been impacted by calibration or laboratory issues could have defenses to their drunk driving charges. Attorneys who practice DUI defense can help their clients apply defenses to their cases when heard at trial.
Source: FindLaw, "BAC Test FAQs," Accessed on Jan. 22, 2015