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Measuring Blood Alcohol Content In Texas: What To Know About The Procedures And Your Rights Involved

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Measuring Blood Alcohol Content In Texas: What To Know About The Procedures And Your Rights Involved


When people drink, alcohol absorbs into the bloodstream through their stomach lining and intestines. This creates a blood-alcohol content level – or “BAC” – that stands as the most commonly used measurement of a person’s intoxication. Generally, BAC measures the amount of alcohol coursing through a person’s bloodstream at the time the test is taken.

The breathalyzer test is what we all think of when it comes to measuring blood-alcohol content. The test is typically considered reliable enough for its results to be admitted at a court trial and used to bring charges against individuals.

Under Texas law, a person is legally intoxicated when their BAC reaches 0.08% alcohol by volume. BAC is calculated in grams per 100 milliliters of blood or 210 milliliters of breath. At 0.08%, a person may feel euphoria and confidence, but also impaired balance, impaired speech and vision, and poor reaction times and self control. Operating a motor vehicle under these conditions – while intoxicated – is a crime under Section 49.04 of the Texas Penal Code.

Standards for Administering a Breathalyzer Test to Measure BAC

To be legally enforceable, a BAC reading taken via breathalyzer must meet certain standards. The breathalyzer must be properly calibrated by the law enforcement agency, with these calibrations recorded in a regularly-used calibration log. This is to ensure that the test is conducted with as much accuracy as possible. Failure to properly calibrate or maintain a record of these calibrations could render the entire test result inadmissible in court.

A breathalyzer used by law enforcement must also meet standards for reliability and quality that other systems – such as those one can purchase for home use – do not meet. The breathalyzer’s mouthpiece must also be changed each time it is used and kept clean. Also, the officer must make sure there are no foreign objects or substances in a person’s mouth that could sway the results.

If all precautions are taken and properly included within a police report, that strengthens the prosecution’s case. If steps are missed or there are issues with the breathalyzer test, the BAC results could be questioned or even excluded through a Motion to Suppress Evidence.

Can a Driver Refuse a Breathalyzer Test?

Texas has an “implied consent” law regarding breathalyzers, meaning each driver taking to the roads is deemed to have consented to a post-arrest breathalyzer test to measure BAC. The breathalyzer must be taken as close to the time of the incident as possible to ensure accuracy, as BAC percentages can rise and fall fairly quickly. (In some cases, a person’s BAC could register higher after they were driving than it was as they were driving, leaving the results subject to challenge.)

A driver can refuse to take the breathalyzer, but would then be subject to an automatic suspension of their driver’s license. (This suspension can be appealed if the person requests an administrative hearing within 15 days of their arrest.) A common misconception is that if the prosecution does not have BAC results from a breathalyzer test, their case falls apart and must be dismissed. However, intoxication can be demonstrated in other ways, with BAC results being one piece of evidence in their case.

Our Pearland, Texas Criminal Defense Attorney Will Fight to Protect Your Legal Rights in a Texas DWI Case

If you have been charged with DWI in Texas and the State obtained a BAC reading through a breathalyzer test, your case is far from over. A skilled and experienced Pearland criminal defense lawyer will examine the test results, the manner in which they were taken, the equipment used, and all other circumstances to fight for your rights and challenge the prosecution. At Keith B. French Law in Pearland, Texas, we will get to know you and help you build a strong defense. To learn more, don’t hesitate to contact the offices of Keith B. French Law, PLLC online or call 832-243-6153 today.


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