Breath tests are commonly used in Dallas DWI cases to provide evidence of intoxication. While many people assume a failed breathalyzer test will lead to a DWI conviction, valid challenges to the accuracy or reliability of the testing machines are sometimes available.

Reliability of Breathalyzer Testing

Some police officers in Dallas carry portable breath testing devices to use during a DWI traffic stop. These portable breathalyzers are good screening devices, but they are not considered forensically reliable and cannot be admitted into court. The other evidentiary breath testing device used in Dallas is called the Intoxilyzer 9000, and the courts to consider it be a reliable instrument.

However, breathalyzer testing is overall much less accurate than a blood test. For this reason, many police departments across the country are moving away from Intoxilyzer use. Currently, however, the state has invested a large sum of money in purchasing new breath testing devices for Texas over the last three years. While state agencies are definitely going to use those devices, individual police departments can make a decision whether or not they are going to have a breath testing program.

Challenging Breath Test Results

The Intoxilyzer machine currently in use is manufactured by a company called CMI and has only been in use for about two years. Breath testing is always open to attack because there are so many different things that can cause a false reading. When determining a strategy in a breath test case, it is helpful to look at breath testing in general, the pitfalls, and the particular device that the defendant blew into. Lawyers also look at the maintenance records and the history of that breath testing device to see if there have been issues in the past.

Breathalyzers can result in false positives or inaccurately high BAC scores when there are issues with the device itself. Additionally, some individuals are simply not good candidates for breath testing due to acetone levels in their breath. This can be due to diabetes or high protein diets that result in ketoacidosis. Other people cannot perform the breath test due to diminished lung capacity. There are a lot of issues with breath testing in general, which is one of the reasons so many police agencies now exclusively conduct blood tests.

Before a breath test result will be sponsored by the state’s expert, certain requirements must be met. One of them is a 15-minute deprivation period, or a period of time during which nothing is introduced into the DWI suspect’s mouth. Sometimes, that rule is violated, allowing an attorney to challenge the resulting evidence. Issues with the paperwork, the calibration of the instrument, or the maintenance of the instrument may also keep that test result from coming into the trial.

Ask a Dallas DWI Attorney About Your Breath Test Result

Overall, the breath test results used in Dallas DWI cases are a ballpark figure and may not accurately represent the accused’s alcohol concentration. However, raising a credible breath test defense in court can be challenging without help from a legal professional. An experienced DWI attorney could carefully scrutinize all the evidence against you and craft a defense tailored to the facts of your case. Call now to schedule a consultation.

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