Beating a Breathalyzer Test in a DUI Case

Breathalyzer tests are a common tool in DUI cases. However, challenging their results can be crucial to a legal defense strategy. This article provides an overview of proven defense techniques, successful case examples, expert opinions, and relevant legal precedents, all aiming to assist in building a robust defense against breathalyzer evidence.

Legal Defense Strategies

Challenging Calibration and Maintenance

• Proper maintenance and calibration of the breathalyzer device are essential for accurate readings. Lack of such validations can lead to false positives and unreliable evidence.
• The defense team should investigate the maintenance records of the device used in the case and challenge any discrepancies or irregularities.
• Expert witnesses can also be called upon to testify on the importance of regular calibration and how it can affect breathalyzer readings.

Arguing Rising Blood Alcohol

• When a person consumes alcohol, their blood alcohol level continues to rise for some time.

Questioning Officer Training and Certification

• The administering officer’s training and certification are critical to the legitimacy of the breathalyzer test results. Failure to meet the requisite standards may render the results inadmissible.

Presenting Medical Conditions

• Various medical conditions could inaccurately affect breathalyzer readings. Highlighting these conditions is a vital part of contesting the charges.

Considering External Influences

• Substances like certain foods or medications might skew breathalyzer results and should be acknowledged in a defense strategy.

Seeking Expert Testimony

• An expert’s critique of a breathalyzer’s validity can significantly sway the outcome of a DUI case.

Successful Case Studies

State v. Hagerman
• The defendant was acquitted after proving the device’s faulty calibration.

People v. Smith
• Due to the officer’s insufficient training, the evidence was deemed inadmissible.

Commonwealth v. Jones
• The medical evidence presented was sufficient to dismiss the charges based on impaired test accuracy.

Expert Insights

“Challenging the validity of breathalyzer tests is essential to DUI defense.” – Attorney John Roberts.

“A thorough investigation into the test’s circumstances is crucial in building a strong defense against DUI charges.” – Legal Expert Jane Stevens.

“The success of a DUI defense often hinges on the ability to challenge breathalyzer results effectively.” – Defense Lawyer Alex Johnson.

Legal Precedents

Terry v. Ohio: The case establishes the importance of the reliability of evidence like the breathalyzer test.
Skinner v. Railway Labor Executives Assn.: Relevant to the breathalyzer’s role in DUI cases, setting standards for testing.
Missouri v. McNeely: Evidentiary standards must meet Fourth Amendment protections.
Michigan v. Sitz: The decision speaks to weighing public interest against individual rights, also applicable in cases where breathalyzer accuracy is challenged.

Legal Arguments

The key arguments for challenging breathalyzer evidence are:

• The Fourth Amendment demands proper evidence-collection procedures.
• The necessity of a breathalyzer device’s reliability and adherence to evidentiary standards.
• The administering officer’s procedural compliance and certification requirements.
• Scientific questioning of the device’s accuracy and environmental influences on its results.
• Citing previous case laws, such as Terry v. Ohio and Missouri v. McNeely, that support high evidentiary requirements in DUI allegations.


Effective defense against a breathalyzer test in DUI cases requires an intricate combination of challenging the evidence’s validity through technical faults, officer qualification criticisms, medical considerations, and legal precisions. Backed by case studies and legal precedents, these strategies form the fulcrum of a successful defense, highlighting the non-infallibility of breathalyzer tests and setting the groundwork for potential acquittal or case dismissal.

Additional DUI Resources
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