Three Powerful Defenses Against Breathalyzer Evidence

Posted by James Ferguson | Feb 01, 2019 | 0 Comments

A breathalyzer test (also known as a breath test) can make or break your DUI case. A breathalyzer that reads Blood Alcohol Content (BAC) as above the legal limit is a strong piece of evidence that the prosecution will yield in court to achieve a DUI conviction. Often times, a DUI offender can pass all field sobriety tests, but still be convicted of a DUI on the basis of a breath test. For this reason, breath test evidence is important to your case.
An experienced DUI attorney will tell you that one of the most powerful defenses against a DUI conviction is to directly attack the breath test. If this test is the only conclusive evidence the state has upon which to bring forth a conviction, then attacking it can bring a dismissal of the state's case. So, hat are the ways to argue against the validity of a scientific testing device?

Maintenance Required
Because of the sensitivity of breathalyzer devices, they are susceptible to mechanical breakdowns and other maintenance issues. The device must be maintained properly and regularly to remain accurate. This includes checking the battery, testing it for mechanical errors, ensuring that all the functions that provide the reading are in working order. If a suspected DUI offender can attest to any mechanical difficulty when the breathalyzer test was being conducted, it is likely to serve as good evidence for a poorly maintained device.

Poor Calibration
Just like a weight scale, a breath testing device must be properly calibrated. Before stepping on a mechanical scale, it is imperative to ensure that the scale is calibrated to zero. This will ensure that when there is weight placed on the scale, it will provide a proper reading. This scenario applies accordingly to the breathalyzer device. The person conducting the test must know how to properly calibrate the device to ensure an accurate reading. If the same device that was used for your testing is placed into evidence, the court can inspect it to ensure that it is fit for the purpose of accurately detecting blood alcohol levels. Similarly, the defense can call an expert who specializes in breath tests to testify as to how the device was improperly calibrated.

Human Error
A simpler ground of defense is to prove that the illegal BAC was a result of human error. For example, an officer takes the breath test of an individual who has been falsely accused of being drunk. The BAC ishows up as being above the legal limit, but it is caused by another chemical source and not alcohol. Another example is when the officer in your case tells you that your BAC is within the legal limit and then you receive a summons for a DUI charge. Perhaps the officer wrote down an illegal BAC amount when your breath test actually concluded otherwise. These cases all contain a factual error, thus leading to a mistaken DUI charge.

Your DUI Attorney
Attorney James Robert Ferguson is an experienced DUI attorney with years of experience defending DUI cases. Driving Under the Influence is a serious crime. If you have been charged with DUI, you need an experienced attorney. Attorney Ferguson is well-versed is DUI defense strategies tailored to your unique case. Attorney Ferguson understands the importance of putting the charge behind you. Call us now for a consultation.

See related blog posts:
Three Common DUI Defenses
Supreme Court: No DUI Blood Draws Without Warrant or Consent

About the Author

James Ferguson

I was born and raised in Memphis, Tennessee. During college, I studied at East Tennessee State University, where I received a Bachelor's in Criminal Justice, which I then followed up with a Master's in Criminology from the University of Memphis. Before beginning my legal career, I worked as a Project Coordinator at the University of Memphis, where I assisted in training law enforcement officers in the Memphis Model of Crisis Intervention Training. The purpose of the project was to provide officers with the tools to deal with citizens in a state of mental crisis. I then went on to study law at the Mississippi College School of Law in Jackson. During law school, I clerked with Victor W. Carmody, Jr., the lawyer who wrote the book on DUI law in Mississippi. I am currently licensed to practice law in both Tennessee and Mississippi, and spend a majority of my time traveling the highways and biways of Mississippi defending those who have been charged with a DUI.


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