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Breathalyzer Calibration as Key to DWI Evidence

On Behalf of | Aug 6, 2015 | Firm News |

The Minnesota law criminalizing breathalyzer test refusals upon arrest recently survived a constitutional challenge in the appellate court. Minnesota law requires submission to a blood, breath or urine test upon the lawful arrest of an intoxicated driver or for an intoxicated person involved in an injury accident, to determine blood alcohol content (BAC) under the implied consent law.

Under that law, a driver implicitly consents to a test of an arresting officer’s choosing within two hours of arrest or risks a minimal one year license suspension (add one year additional for each prior DWI conviction) for refusing to take the test, thus violating the statute. An officer must inform the driver that refusal to take the test is a crime.

Refusing an ordered breathalyzer test does not necessarily avoid conviction of a DWI as the test merely provides proof of a BAC over .08%, the legal limit for persons over 21. Other evidence, such as the arresting officer’s observations also supports a DWI conviction, however. In any event, breathalyzer tests results often end up in trials for DWI convictions, so the test results are critical.

Breathalyzers, which a driver blows into, register a driver’s BAC level, which is then used as evidence of presumed intoxication in a court of law. If registered at higher than the legal .08%, results of the device prove a defendant’s BAC once an arresting officer’s department proves that the breathalyzer works properly. Otherwise, the results are subject to challenge in court. Calibrating and maintaining Breathalyzers insure accurate results as reliable evidence.

For court purposes, Breathalyzer test results from devices on a list of acceptable devices that are properly maintained and regularly checked for accuracy are likely admitted as evidence if the certified operator of the device properly trained to use that particular device that he or she used according to his or her training. In addition, the officer must insure the test taker did not burp, eat, drink, vomit or smoke for a specific period of time before testing, all of which can skew results. And finally, the device must have produced minimally two readings within .02 of one another.

Deviations from any of these calibration and operation factors are subject to challenge by the test taker, i.e., whether the device’s readings is evidence of intoxication. Maintenance and calibration records of the breathalyzer in question support either side’s evaluation of the evidence. If a defendant successfully discredits the Breathalyzer evidence, the state bears the burden to prove intoxication some other way.

An experienced Minneapolis DWI Lawyer knows the specifications for proper calibration and maintenance of the state’s Breathalyzers; contact us for advice about your DWI matter.