Yes. You can be charged with DWI in Dallas, Texas, even if your BAC is 0.00. A Drug DWI does not require alcohol or a specific drug concentration. Prosecutors must prove that drugs caused a loss of normal mental or physical faculties, usually relying on officer observations, standardized field sobriety tests, and sometimes blood testing.
Because Texas has no per se drug-concentration limit for ordinary DWI, these cases can present significant disputes over whether a drug actually caused impairment at the time of driving.
Last updated: August 2026
How Can Someone Be Charged With DWI Without Alcohol?
Many drivers believe a DWI in Dallas only applies if alcohol is involved. That belief is incorrect.
In Texas, you can be arrested and prosecuted for DWI even if your breath test shows 0.00 BAC, if police believe drugs—legal or illegal—impaired your ability to drive. These cases are known as Drug DWIs, and they are becoming increasingly common in Dallas County.
This guide explains how 0.00 BAC drug DWI cases work in Dallas, what evidence police may rely on, what the State must prove, how toxicology and DRE evidence may be used, and what issues a defense attorney may examine.
What Is a Drug DWI (0.00 BAC) in Texas?
A Drug DWI (0.00 BAC) occurs when a driver is accused of operating a motor vehicle in a public place while intoxicated by drugs rather than alcohol, even though breath testing shows no measurable alcohol.
Under Texas law, intoxication includes impairment caused by:
- Prescription medications
- Illegal drugs
- Over-the-counter medications
- A combination of substances
There is no numeric legal limit for drugs, unlike alcohol.
Related: Texas drug laws
How Texas Law Allows DWI Charges With No Alcohol
Texas law does not require alcohol to support a DWI charge. Under Texas Penal Code § 49.01, a person can be considered intoxicated in two ways:
- Having an alcohol concentration of 0.08 or higher, or
- Not having the normal use of mental or physical faculties because of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance.
In a 0.00 BAC drug DWI case, prosecutors cannot rely on the 0.08 alcohol-concentration definition. Instead, they generally must prove that a drug or other qualifying substance caused the loss of normal mental or physical faculties.
Because Texas has no general per se drug-concentration limit for DWI, these cases often depend on evidence such as officer observations, field sobriety testing, Drug Recognition Expert evaluations, toxicology results, and other evidence of the driver's condition at the time of driving.
What the State Must Prove in a Dallas Drug DWI (0.00 BAC)
To convict someone of a drug DWI, the State generally must prove beyond a reasonable doubt that:
- The person was intoxicated;
- While operating a motor vehicle;
- In a public place.
In a 0.00 BAC drug case, the State must establish intoxication through loss of the normal use of mental or physical faculties and connect that loss to a drug, controlled substance, dangerous drug, another qualifying substance, or a combination of substances.
What Substances Can Lead to a Drug DWI in Texas?
Substances that can be involved in a Texas drug DWI investigation include:
- Marijuana (THC)
- Prescription medications (Xanax, Valium, Adderall, opioids)
- Sleep aids and muscle relaxers
- Combinations of medications
- Alleged “poly-substance” use
Important: Lawful prescription use does not automatically equal illegal driving. The State must still prove actual impairment.
How Dallas Police Investigate Drug DWI Cases
When alcohol testing does not establish intoxication, officers investigating suspected drug impairment may rely on:
- Driving behavior (weaving, delayed response, slow driving)
- Physical appearance (red eyes, confusion, tremors)
- Field sobriety tests
- Statements by the driver
- Admissions of medication or substance use
- Drug Recognition Expert (DRE) evaluations
- Blood test results (if obtained)
The significance and reliability of this evidence depend on the circumstances of the individual case.
What Do Field Sobriety Tests Show in a Drug DWI Case?
Standardized Field Sobriety Tests were developed and validated primarily in the context of alcohol impairment. Although officers also use roadside observations and SFST performance when investigating suspected drug impairment, the tests do not provide a numerical measurement of drug concentration or establish by themselves that a particular drug caused impairment.
Drug Recognition Experts (DREs): What They Are—and What They Are Not
A DRE evaluation is an officer's trained assessment, not a laboratory measurement of drug concentration. The defense can examine whether the officer followed the 12-step protocol, whether the observations support the opinion, whether medical conditions provide alternative explanations, and whether toxicology findings are consistent with the officer's conclusions.
Blood Tests in Drug DWI Cases: What They Do—and Don’t Prove
Blood testing is common in Drug DWI cases, but it is widely misunderstood.
Key realities:
- There is no illegal drug level for most substances
- Presence ≠ impairment
- Many drugs remain detectable long after their effects wear off
- Lab delays of 3–9+ months are common
The defense may also examine collection procedures, sample storage, chain of custody, laboratory methodology, measurement uncertainty, and the relationship between the reported concentration and impairment. A positive blood test does not prove intoxication.
Drug DWI vs Alcohol DWI in Dallas
| Issue | Alcohol DWI | 0.00 BAC Drug DWI |
| Per se threshold | 0.08 alcohol concentration | No general per se drug threshold |
| Breath testing | May establish alcohol concentration | Does not measure drug concentration |
| Blood testing | Can measure alcohol concentration | May identify and quantify drugs/metabolites |
| Intoxication theory | 0.08+ or loss of normal faculties | Loss of normal faculties |
| DRE evaluation | Less central in a typical alcohol case | May be used in suspected drug impairment cases |
Drug DWI Timeline in Dallas
A drug DWI case in Dallas may follow these general stages:
- Traffic stop: An officer observes driving behavior or another reason for the stop.
- Roadside investigation: The officer may ask questions and administer standardized field sobriety tests.
- Arrest: If the officer has probable cause to believe the driver is DWI, the driver may be arrested.
- Blood testing: Police may request a blood specimen or seek a warrant for a blood draw when appropriate.
- Toxicology analysis: A laboratory may test the blood for drugs, medications, or metabolites.
- Pretrial proceedings: The defense can review police video, field sobriety testing, DRE evidence, toxicology results, and the legality of the stop, arrest, and blood draw.
- Resolution or trial: Depending on the evidence, the case may be dismissed, resolved through negotiations, or proceed to trial.
Drug DWI cases can take longer to investigate than alcohol cases when prosecutors are waiting for toxicology results.
Related: Dallas drug crimes
Will You Go to Jail for a Drug DWI in Dallas?
Jail is possible for a drug DWI in Dallas, but the potential sentence depends on the specific charge, prior DWI history, aggravating circumstances, and how the case is resolved. A drug-based DWI generally follows the same Texas DWI penalty framework as an alcohol-based DWI.
Related: Dallas drug crimes lawyer
License Consequences: ALR in Drug DWI Cases
A 0.00 BAC drug DWI does not automatically trigger an Administrative License Revocation (ALR) suspension simply because a blood test detects drugs. For an adult noncommercial driver, ALR commonly arises when the driver refuses to submit a requested breath or blood specimen. A test-failure suspension, by contrast, generally requires an alcohol concentration of 0.08% or more.
If you are served with a DIC-25 following a refusal, you generally have 15 days from service to request an ALR hearing.
Common Defenses in Drug DWI (0.00 BAC) Cases
Effective defenses often include:
- No reliable proof of impairment
- Medical explanations for observed behavior
- Improper traffic stop
- Invalid arrest
- Blood test timing and relevance
- Constitutional violations
- Whether toxicology results actually support impairment at the time of driving
- Errors or inconsistencies in a DRE evaluation
What a Drug DWI (0.00 BAC) Does NOT Mean
It does not mean:
- Drugs were illegal
- You were intoxicated
- Conviction is automatic
- A specific drug level is required
- Defense options are limited
What to Do If You’re Arrested for a Drug DWI in Dallas
After a drug DWI arrest, review any driver's license paperwork promptly, preserve documents relating to prescriptions or medical conditions, avoid discussing the facts of the case publicly, and speak with a DWI attorney about the criminal charge and any applicable ALR deadline.
Bottom Line
A 0.00 BAC does not prevent a Texas drug DWI prosecution, but it changes what the State must prove. Without a per se drug limit, the case generally turns on whether prosecutors can establish that a drug or other qualifying substance caused the loss of normal mental or physical faculties while the person was driving.
FAQs: Drug DWI (0.00 BAC) in Dallas, Texas
Can I really be charged with DWI if my BAC is 0.00?
Yes. Texas law allows DWI charges based on drug impairment alone.
Is a Drug DWI harder to prove?
Possibly. It can present different proof problems. In a 0.00 BAC drug DWI, prosecutors cannot rely on the 0.08 alcohol-concentration definition of intoxication. They generally must prove loss of normal faculties through observations, testing, toxicology and other evidence.
Does a positive drug test mean I’m guilty?
No. Presence does not prove impairment at the time of driving.
Are prescription drugs a defense?
Yes. A valid prescription does not prevent a DWI charge if the State can prove the medication caused intoxication. However, lawful use alone does not establish that the driver was impaired.
Will a drug DWI stay on my record?
It depends on the outcome. A DWI arrest can remain on criminal-history records unless the case qualifies for and receives an expunction or other available record-clearing relief. Eligibility depends on how the case is resolved and other statutory requirements.
About Michael & Associates
Michael & Associates is a Texas-based criminal defense firm that represents clients in Dallas County misdemeanor and felony cases, including DWI, DUI, drug DWI, marijuana DWI, drug charges, assault and domestic violence, theft, and shoplifting. The firm regularly handles DWI cases involving complex forensic evidence, including blood toxicology, gas chromatography, breath testing, Drug Recognition Expert evaluations, and the scientific reliability of chemical-test results.
Contact us today to schedule a free case review.
Sources: Michael & Associates research and internal case data, Texas Penal Code, Texas Department of Public Safety, Dallas County DA's Office, Texas Health and Safety Code, Texas Controlled Substances Act.
Note: This article was written by Ben Michael, Managing Partner of Michael & Associates (Texas Bar Card #24088055). It was originally published on January 14, 2026, and has been reviewed for accuracy by the Michael & Associates research team and the firm's Dallas attorneys, who regularly handle DWI cases involving blood toxicology, field sobriety testing, Drug Recognition Expert evaluations, and other evidence of alleged drug impairment.
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