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What are Some of the Ways to Challenge an OUI Arrest When I Failed a Breath Test?

What are some ways that a Massachusetts OUI lawyer can challenge an arrest with breath test evidence. One method is by retaining an expert to explain to the jury why the results may be inaccurate in your particular case. Breath testing depends on a number of different assumptions. These assumptions do not apply to everyone who takes the test. A breathalyzer test result may not be accurate in your particular case.

• Understanding the margin of error of breath test results

An expert can testify to a number of different things. First the expert can testify to the margin of error for the breathalyzer machine. The breath test machine has a margin of error like any machine and an expert can explain to the jury factors that account for the margin of error of the machine.

• Explaining the assumptions that the machine is making, everyone is the same

The breathalyzer machine assumes that everyone submitting a sample has the same characteristics. This accounts for the error rate of the machine. An expert can testify to the assumptions the machine makes, some of the assumptions are that the sample is deep lung air, the person’s body temperature is a certain number and is not elevated- in some states the machine will actually take the temperature of the person and adjust the breath test result accordingly.

• Using the data produced by the machine to show the results are inaccurate

In one case where an expert was employed, an expert testified for a client of mine that given the high volume of breath in the machine and the officer’s observations, that the machine did not use deep lung air. The expert testified that the officer’s testimony coupled with the results produced by the machine and the data show that the machine most likely did not read a deep lung air sample. This was in a case where the breath test result was .10, the defendant performed relatively well in the field test and the expert testimony, when unchallenged, the defendant was found not guilty on both the impairment theory and being over 0.08.

• Medical conditions impacting breath test results

An expert can also explain medical conditions that could impact the reliability of the test, such as gastric reflux, diabetes, asthma and other medical conditions that may impact the results of the breathalyzer test.

• When the Defense calls an Expert, typically the Commonwealth does not present an expert to rebut the testimony

The breath test expert is typically the only person who actually knows how the machine works. Generally, the commonwealth witnesses will testify simply that the machine was turned on, they pushed the buttons and it appeared to be working. The commonwealth does not usually call anyone from the office of alcohol testing who can explain how the machine works. The officers that test the machine do not know how the machine works, they testify simply that they pushed the buttons and the machine produces a result that they believe is accurate and reliable. So when a breath test expert is presented, the defense is teaching the jury more about the machine than the jury will learn from the commonwealth. Additionally, an expert may help in getting the breath test excluded from evidence so it is not even heard by the jury.

While an expert is expensive, if you are going to do everything that there is to fight an OUI charge and the breath test result, it is extremely valuable asset for the defense and helps expand the range of question and evidence that can be put before the jury. If you have any questions about whether a breath test expert could assist in your case, feel free to call me at 781-686-5924 or 508-455-4755.

Client Reviews
Michael was very professional and explained the process clearly and told us to be patient. After one year the charges got dismissed in the trial. Excellent knowledge of the court systems in the area of Boston. Would highly recommend him Ashwani
A careless decision on my part left me facing charges which would have severely hampered my ability to stay employed and support myself. But attorney DelSignore's skillful analysis and challenging of the evidence against me resulted in a conviction on a lesser charge. Now I'll be able to go on with my life, having learned a lesson I'll never forget. Thank you, Michael. Scott
Mike stuck with my case for 3.5 years and always kept me informed regarding the status. Ultimately, because of his due diligence, we ended up with an OUI not guilty verdict. This case could have gone many ways but his thorough review of the case and exceptional preparedness for trial ultimately drove a positive outcome. Thank you Mike! David
Michael DelSignore did an amazing job with my case! He was always available to answer any questions I had and helped walked me through the entire process. I could not have done it without them! I highly recommend choosing this law firm to deal with your legal needs, you will not be dissatisfied. Ashley
I cannot express the gratitude towards Michael for his amazing work and help. It was a very stressful event and they certainly put me at as much ease as possible. From start to finish it took 14 months and all the way through they were both very engaged with me. Today was worth the wait, Michael was great in court and I was rightfully found not guilty. I would recommend Michael over and over again. Claire