Common Types Of Evidence Used In Texas DWI Cases

A DWI charge in Texas is not merely a traffic ticket, but a criminal offense that can result in life-altering consequences like jail time, hefty fines, a suspended license, and a lifetime criminal record. The state builds its case upon evidence. Having an idea of what type of evidence they're using, how they acquire it, and, more importantly, how to disprove it is your first line of defense.

The outcome lies in the admissibility and potency of this evidence. If you're searching for a Frisco criminal lawyer after a DWI arrest, knowing the common types of evidence used is vital. You should not head into court blind. This is an entire guide that breaks down each of the primary types of DWI evidence in Texas, giving you the information you need to start building a solid defense plan today. Knowledge is power when your liberty is on the line.

1. The Initial Stop: Was it Legal? (Observational Evidence)

It all begins with the traffic stop. Police only have "reasonable suspicion" that you broke a traffic law or were driving dangerously in order to pull you over. Evidence in this case includes:

Officer Observations: Weaving, speeding, running stop signs, reckless braking. Dash cam videos often record this.

Dispatch Records: Radio logs that record the reason for the stop.

Why it Matters: If the stop was not legitimate, all subsequent evidence (SFSTs, breath tests) could be invalidated. A competent defense attorney examines the justification for the stop closely.

2. The Officer's Initial Impressions: Indications of Impairment

When he arrives at your vehicle, the officer notices immediate signs:

Physical Signs: Watery/bloodshot eyes, slurred speech, smell of alcohol on breath, flushed face, fumbling with papers.

Behavioral Indicators: Confusion, admitting drinking ("I had two beers"), inconsistent answer, agitation.

Vehicle Interior: Open liquor, drug paraphernalia in view.

Why it Matters: These personal experiences are the basis on which you are asked to take field tests. They can be rebutted on officer bias, medical reasons, or external circumstances.

3. Field Sobriety Tests (SFSTs): The Walk-and-Turn, etc.

Standardized Field Sobriety Tests (SFSTs) are body coordination exercises:

The Big Three: Horizontal Gaze Nystagmus (HGN - eye jerking), Walk-and-Turn, One-Leg Stand.

Officer Scoring: They look for definite "clues" of impairment (e.g., swaying, stumbling, improper turns).

Non-Standard Tests: Alphabet recital, finger-to-nose (less reliable, usually not standardized).

Why it Matters: SFSTs are very subjective and notoriously inconsistent. A number of variables (uneven roads, poor lighting, medical issues, nervousness, footwear, or improper officer instructions) can invalidate results. Video proof (dashcam/bodycam) is critical here.

4. Breathalyzer Test: Preliminary & Evidential

Texas breath tests are performed at two stages:

Preliminary Breath Test (PBT): A Portable device is used on the road while stopped. Results are not typically admissible at trial to determine BAC level, but are admissible to find probable cause of arrest.

Evidential Breath Test (EBT): Given at the station on a larger, accepted machine (like the Intoxilyzer 9000). Results may be presented as evidence of your Blood Alcohol Concentration (BAC).

Why it Matters: Breathalyzers must be calibrated, maintained, and operated by certified operators. Certain medical conditions (acid reflux, diabetes), mouth alcohol, some diets, and insufficient observation times can lead to false high test results. Challenging the machine and the administration of the test is common.

5. Blood Tests: The Most Direct (and Invasive) Evidence

Blood tests provide the most direct measurement of BAC or drug presence.

Voluntary Consent: You may consent to a blood draw.

Forced Blood Draw (Warrant): The officers typically obtain a search warrant from the judge, especially in accident injuries, prior DWIs, or if you decline the breath.

Forced Blood Draw (No Warrant - "No Refusal"): In some circumstances defined by law (for example, accident with death/severe injury, child passenger, prior intoxication offenses), blood may be extracted without a warrant.

Why it Matters: Blood evidence is powerful but vulnerable. Chain of custody errors, incorrect storage and handling, contamination, qualifications of the lab analyst, and test methodology are all areas of supreme significance. Raising BAC defense (BAC was below the limit when the driver drove the vehicle, but rose by the time it was tested) can also be employed.

The prosecution's case for DWI is built brick by brick using different types of evidence. Each piece of evidence, from the original stop justification to the chemical test report, contains potential weaknesses that a solid defense can challenge. Never assume the evidence against you is solid or impenetrable. Having these common kinds of evidence empowers you to ask the right questions and request the zealous defense you're entitled to.

Creating a winning strategy involves dissecting every element of the state's case, fighting against improper procedures, flawed tests, and abuses of your rights. Don't navigate this minefield of evidence alone. Protect your future. Contact a seasoned Frisco criminal defense attorney today. They are aware of how to dissect the specific evidence in your case, find the best defenses, fight for evidence that was suppressed, and pursue vigorously the best possible outcome. Act now; your freedom is on the line.