Can an Improperly Administered Breath Test Be Challenged in a Texas DWI Case?

Many Texas DWI cases rely heavily on the results of a breath test. Prosecutors often present the numerical reading as powerful scientific evidence that a driver was intoxicated. However, the accuracy of a breath test depends on far more than simply blowing into a machine. Officers must follow established procedures before, during, and after the test to help ensure the results are reliable.

If those procedures are not followed, the validity of the breath test may be called into question. An improperly administered breath test does not automatically result in dismissal of a DWI charge, but it may create opportunities to challenge one of the prosecution’s most important pieces of evidence.

If you were arrested for DWI in Longview or elsewhere in East Texas, an experienced DWI defense attorney will carefully examine how the breath test was conducted and whether every required procedure was followed.

Breath Testing Is a Scientific Process

Many people assume a Breathalyzer machine simply provides an accurate reading every time it is used. In reality, breath testing is a scientific procedure that depends on both properly functioning equipment and proper administration by the officer conducting the test.

The machine itself is only one part of the process. The reliability of the final result also depends on whether the officer followed established testing protocols.

Even small procedural mistakes may affect the confidence that can be placed in the reported result.

Officers Must Follow Required Testing Procedures

Before administering a breath test, officers are generally expected to follow specific procedures designed to reduce the possibility of inaccurate readings.

One important step involves observing the individual for a designated period before testing. During that observation period, officers are generally watching to ensure the person does not place anything in their mouth, vomit, burp excessively, or engage in conduct that could affect the breath sample.

If the observation period is interrupted or shortened, questions may arise regarding whether the reported result accurately reflected deep lung air rather than residual alcohol inside the mouth.

An attorney may carefully review reports, testimony, and available video footage to determine whether the required procedures were actually followed.

Residual Mouth Alcohol Can Affect the Reading

Breath testing is intended to measure alcohol that has been absorbed into the bloodstream and transferred into the lungs.

However, alcohol remaining inside the mouth may temporarily produce an artificially elevated reading.

Residual mouth alcohol may result from:

• Recent alcohol consumption.
• Burping.
• Vomiting.
• Acid reflux.
• Certain dental products.
• Mouthwash containing alcohol.

This is one reason why observation periods are considered an important part of the testing process.

The Officer’s Training May Become Relevant

Not every officer is authorized to administer breath tests. Departments generally require specialized training before officers may operate breath testing equipment.

An experienced DWI defense attorney may investigate whether the officer administering the test had the appropriate certifications and whether those certifications remained current at the time of the arrest.

If training records reveal deficiencies, that information may become relevant when evaluating the reliability of the test.

Environmental Conditions May Influence Testing

Although breath testing equipment is designed for law enforcement use, outside conditions may sometimes affect the testing process.

Factors such as electrical interference, equipment malfunctions, or improper maintenance may influence how the machine performs.

While these situations are not common, they demonstrate why breath test results should not automatically be accepted without careful review.

Maintenance records, inspection reports, and repair histories may provide valuable information regarding the condition of the testing instrument.

The Breath Test Is Only One Part of the Evidence

A breath test does not exist in isolation. Prosecutors typically present it together with the officer’s observations, field sobriety test performance, driving behavior, and any statements made during the investigation.

Likewise, the defense should evaluate the breath test alongside all other available evidence.

For example, if a relatively high breath test result appears inconsistent with body camera footage showing clear speech, steady balance, and appropriate responses, additional questions may arise regarding the accuracy of the testing process.

Looking at the entire investigation rather than focusing on a single number often provides a more complete understanding of the case.

Documentation Can Reveal Important Information

Every breath test generates records beyond the numerical result itself.

Depending on the circumstances, an experienced defense attorney may obtain documentation concerning the testing instrument, maintenance history, calibration records, quality assurance procedures, and the officer’s administration of the test.

Reviewing these materials sometimes uncovers inconsistencies or procedural issues that are not apparent from the police report alone.

Because prosecutors frequently rely heavily on breath test evidence, carefully examining the underlying documentation is often an essential part of preparing a strong defense.

Scientific Evidence Should Be Carefully Examined

Jurors often place significant weight on scientific evidence because it appears objective. However, scientific evidence is only as reliable as the procedures used to obtain it.

An improperly administered breath test may produce results that are less reliable than they initially appear. For that reason, experienced Texas DWI defense attorneys routinely investigate every aspect of the testing process rather than simply accepting the reported number.

If weaknesses exist in the administration of the breath test, those issues deserve careful consideration during negotiations, pretrial motions, or trial.

Every DWI Case Deserves a Thorough Investigation

No single piece of evidence determines the outcome of a Texas DWI case. Every investigation should be carefully reviewed to determine whether police officers followed proper procedures and whether the prosecution’s evidence is reliable.

An experienced DWI defense attorney will evaluate the breath test together with the entire investigation, including the traffic stop, field sobriety testing, video evidence, witness statements, and chemical testing procedures.

When all of the evidence is examined together, important defenses may emerge that are not immediately obvious. Protecting your rights begins with ensuring that every step of the investigation complied with the law and accepted scientific standards.

Call The Law Office of Alex Tyra, P.C. For Your Free Consultation

If you’ve been charged with DWI in Longview or anywhere in East Texas, don’t wait. The clock starts ticking the moment you’re arrested, and every decision you make from here on out matters. The Law Office of Alex Tyra, P.C. is ready to help you protect your future, your license, and your wallet.

Call us today at (903) 753-7499 to schedule your free consultation and take the first step toward fighting your DWI charges.