Yes. About one in 10 DWI arrests in Texas involves no chemical test result at all. The defendant either refused, no test was administered, or the prosecution proceeded on impairment evidence alone. Understanding why requires understanding how Texas defines intoxication because the legal definition is broader than most people realize.
How Texas Defines Intoxication
Texas Penal Code §49.01(2) defines intoxication in two distinct ways. The first is the per se definition: a blood alcohol concentration of 0.08 percent or higher. The second is the impairment definition: not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body.
Either definition is sufficient to support a DWI conviction. A prosecutor does not need a chemical test result to prove the second definition. They need evidence that the defendant’s faculties were impaired at the time of driving and that evidence can come entirely from the officer’s observations, the defendant’s driving, and the results of field sobriety tests.
This is not a loophole or an edge case. It is the statute. Texas DWI law was written to cover both the driver who tests above the legal limit and the driver who is visibly impaired regardless of what a machine would show.
How the Prosecution Builds a No-Test DWI Case
When there is no breath or blood test result, prosecutors build their case from the following sources of evidence:
The Stop and the Driving Pattern
Many DWI cases begin with a traffic stop based on observed driving behavior: weaving between lanes, driving significantly below the speed limit without apparent cause, running a red light, stopping erratically, or following too closely. The officer’s description of the driving pattern becomes part of the probable cause record and, if the case goes to trial, part of the evidence of impairment. Dashcam footage showing the driving is often admitted. The driving pattern is frequently the most compelling evidence a jury sees.
The Officer’s Personal Observations
After the stop, the officer documents everything: the odor of alcohol, the condition of the eyes, the coherence of the driver’s speech, the ability to locate documents, the manner of exiting the vehicle, the stability of the gait. Each of these observations goes into the police report and into the officer’s trial testimony.
These observations are subjective. An odor of alcohol does not establish how much was consumed or whether the driver was impaired. Red or watery eyes have causes unrelated to alcohol. Slurred speech can result from fatigue, medical conditions, or anxiety. The subjectivity of these observations is where the cross-examination of the arresting officer begins.
Field Sobriety Tests
The three Standardized Field Sobriety Tests (Horizontal Gaze Nystagmus (HGN), walk-and-turn, and one-leg-stand) were developed by NHTSA and validated under controlled research conditions. In the field, they are administered roadside, often at night, on uneven pavement, in traffic, under the stress of a law enforcement encounter. Each test has specific administration requirements. The HGN test requires a precise number of passes at a precise stimulus speed. The walk-and-turn and one-leg-stand have specific instruction and scoring requirements.
Deviations in administration affect the validity of the results. Deandra Grant is a trained SFST instructor. When she reviews an officer’s SFST performance in a DWI case, she is evaluating it against the same NHTSA standards the officer was trained to follow. Errors in technique, scoring, or instruction are identified and challenged. These are not minor technicalities. They are the standards the government set for itself, and the officer’s compliance with them is what gives the tests whatever validity they have.
Statements Made at the Scene
What a driver says during a DWI stop is part of the evidence. Admitting to having had “a couple of drinks,” naming the bar, identifying when the drinking stopped: all of this goes into the police report and can be used at trial. Drivers are not required to answer questions beyond providing their license, registration, and proof of insurance. The right to remain silent applies at a DWI stop, and exercising it is not itself evidence of guilt.
Video Evidence
In-car dashcam footage and body camera footage are now standard in most North Texas DWI arrests. This footage captures the driving, the stop, the field sobriety test performance, and the interaction at the scene. Video is a double-edged source of evidence. It can corroborate the officer’s account, but it can also directly contradict it. An officer who describes a defendant as “unsteady on their feet” and “unable to follow instructions” can be challenged when the body camera shows something different. Defense counsel always requests the complete, unedited footage.
Drug Impairment DWI: No Breath Test, No BAC Number
The impairment definition of intoxication under §49.01(2) covers not just alcohol but controlled substances, prescription drugs, dangerous drugs, and “any other substance.” A driver impaired by marijuana, opioids, benzodiazepines, antihistamines, or any other substance (including legally prescribed medications) can be charged with DWI. Breath tests do not detect drug impairment. The prosecution’s evidence in a drug DWI case is the officer’s observations, the field sobriety test performance, and typically a blood test result.
Drug recognition expert (DRE) evaluation is sometimes used in drug impairment cases. A DRE officer follows a 12-step protocol designed to identify the category of drug causing impairment. DRE evidence is contested at the trial court level on Daubert/Kelly grounds in Texas, and the methodology has limitations that experienced DWI defense counsel challenges. Importantly, a positive blood test for a drug does not automatically establish impairment at the time of driving. THC blood concentration, for example, does not correlate reliably with impairment in the way that blood alcohol concentration does. The presence of a substance in the blood is not the same as impairment by that substance.
What the Defense Looks Like in a No-Test DWI
Without a chemical test result, the prosecution has no number. That changes the defense landscape in important ways.
The entire case rests on the officer’s credibility and the SFST results. There is no BAC reading to overcome. The jury must decide whether the officer’s observations (the driving, the smell, the eyes, the speech, the field sobriety performance) prove beyond a reasonable doubt that the defendant had lost the normal use of mental or physical faculties. That is a higher bar than pointing to a number that exceeds the legal limit.
SFST administration errors carry more weight. When the field sobriety tests are the primary evidence of impairment, the technical validity of those tests becomes the center of the defense. An officer who deviated from NHTSA protocol in administering or scoring the HGN, walk-and-turn, or one-leg-stand has weakened the evidentiary foundation the entire case rests on. Identifying those deviations requires someone trained to know what to look for.
Article 38.23 still applies. Texas’s exclusionary rule carries no good faith exception. If the traffic stop was unlawful (if the driving behavior the officer described does not actually constitute a traffic violation, or if the officer’s account of the stop is not supported by the dashcam footage) everything that followed is subject to suppression. A no-test DWI that began with a bad stop is a case that may not survive a suppression hearing.
The video is essential. Defense counsel requests the complete dashcam and body camera footage in every case. In a no-test DWI, where the officer’s subjective observations are the primary evidence, footage that contradicts those observations can be determinative.
What About a BAC Below 0.08 Percent?
A breath or blood result below the per se limit of 0.08 percent does not end the DWI case. The prosecution can still proceed under the impairment definition if the evidence supports it. A driver who tests at 0.06 percent but whose driving and field sobriety performance suggest impairment can be charged under Texas law.
This cuts both ways. A below-limit test result is powerful defense evidence. It directly undermines the per se theory and forces the prosecution to rely entirely on the impairment theory. It shifts the jury’s focus from a number to a judgment call about the officer’s observations. In many cases, a below-limit result (while not a get-out-of-jail-free card) substantially improves the defense position.
The Bottom Line
A breath test failure is one way to prove DWI in Texas. It is not the only way, and the absence of a failing test does not mean the case goes away. The impairment definition of intoxication is broad, and prosecutors use it routinely in cases where no chemical test was administered or where the result came back below the legal limit.
The defense in a no-test DWI is built on challenging the lawfulness of the stop, the validity of the field sobriety test administration and scoring, the credibility of the officer’s observations, and the video record. These cases are winnable but winning them requires a defense attorney who understands the forensic science of field sobriety testing, not just the law.
Deandra Grant Law defends DWI charges throughout Dallas County and North Texas, including cases involving no chemical test, below-limit results, and drug impairment. Call (214) 225-7117 for a free, confidential consultation.
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