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Our Minnetonka DWI Defense Attorneys Explain the Physical Inability Defense

When you are suspected of DWI, the officer typically requests that you perform field sobriety tests and a breathalyzer test. The breath test requires you to expel a certain amount of breath into the testing device.  If this minimum volume is not produced, the officer will typically treat the failure as a “refusal,” which can result in the loss of your driver’s license and increased criminal punishments.  In this blog, our Minnetonka DWI defense lawyers discuss how we might assert a physical inability defense if you are cited for a “refusal” because you did not produce enough air.

Science Behind the Physical Inability Defense

A breath test requires two legitimate samples, so if one of them is deficient, a refusal can result.  A valid test result requires 1.5 liters of air from the deep lungs at a flow rate of 3.0 liters per minute. While most motorists can expel enough air for a valid test with enough effort, there are physical and medical limitations that might prevent a driver from producing sufficient breath.

If you use a two-liter soda bottle as the standard, you must produce enough air to fill the bottle to ¾ of its capacity.  Multiple physical causes might limit a driver’s ability to produce a sufficient sample.  Examples of medical conditions or injuries that might impede a motorist ability to perform a breath test include Chronic Obstructive Puliminary Disease (COPD), lung cancer, asthma, or injuries incurred in an accident.

Strategy of the Physical Inability Defense

Under Minnetonka law, physical inability constitutes an affirmative defense which means that the accused has the burden of proof regarding his or her capacity to produce a sufficient breath sample.  Our Minneapolis DWI defense lawyers have had success challenging DWI refusal cases using the inability defense.

Typically, a successful physical inability defense involves producing evidence of a medical condition or injury that limits your lung capacity.  Pulmonary function tests (PFTs) related to a lung disorder are one form of evidence we might use.  Spirometry is the most common and initial lung function test used by doctors.  This test measures the volume and time required for you to move air out of your lungs.

Along with medical records that include such diagnostic testing and treatments, we might also present testimony from a pulmonary doctor.  A medical expert often will be necessary to combat the State’s expert if they call one to testify.

Under Minnesota’s “implied consent” law, an individual who drives a motor vehicle consents to breath, blood, or urine test to determine if the motorist is under the influence of alcohol or drugs.  Refusal to submit to an “evidentiary” breath test following a lawful arrest constitutes a separate crime that exposes a motorist to penalties independent of the driver’s DWI criminal case.

A refusal can possibly result in conviction of a gross misdemeanor and carry a punishment of 12-month revocation of your driver’s license or more and required installation of an ignition interlock device.

If you are asked to take a breath test in Minnetonka, you have the legal right to consult with an experienced DWI defense attorney.  Motorists should take advantage of this right because the officer has no regard for your legal rights since his goal is to gather evidence to establish you were driving while intoxicated.

If your refusal was based on the failure to produce sufficient air for the test, an attorney could help you assemble the proper medical records and experts.  Even with this type of evidence, the prosecutor will likely challenge this defense by arguing the evidence you have produced does not indicate you cannot produce sufficient breath volume for a valid test.

The officer might testify that it appeared you were not trying to use your full lung capacity or that you were intentionally expelling air around the outside of the mouthpiece of the breath testing device.

Have More Questions? Seek Legal Advice Today!

If you are facing the charge of a breath test refusal, we invite you to speak to a Minnetonka DWI Lawyer at Gerald Miller, P.A. as soon as possible.  The sooner you contact us, the sooner we can start protecting your rights.

Contact us today to schedule your free and confidential case evaluation.

About the author

Gerald Miller

Gerald Miller is a top-notch and experienced DWI/DUI lawyer at Gerald Miller P.A. in Minneapolis, MN. He has more than 35 years of experience in Criminal Defense practice. He has also been a mentor to numerous DUI/DWI defense attorneys.

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