Texas Intoxication Law
What Counts as Intoxicated in Texas? DWI Below 0.08
Texas gives the State two independent ways to allege intoxication: loss of the normal use of mental or physical faculties because of an introduced substance, or an alcohol concentration of 0.08 or more. The first theory is why a DWI allegation can exist below 0.08 and why drugs, prescriptions, and combinations can support a case without an alcohol number.
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Two independent definitions of intoxicated
Texas Penal Code section 49.01(2) uses the word or. The State does not have to rely on both theories in the same case.
Loss of normal faculties
The first theory asks whether alcohol, a controlled substance, a drug, a dangerous drug, a combination, or another substance caused the person to lose the normal use of mental or physical faculties. It does not contain a numerical threshold.
Alcohol concentration of 0.08 or more
The second theory is numerical. Texas defines alcohol concentration by grams of alcohol per 210 liters of breath, 100 milliliters of blood, or 67 milliliters of urine. Statute-based analysis therefore uses the broader term alcohol concentration, not only blood alcohol concentration.
Why a Texas DWI can be alleged below 0.08
A result below 0.08 does not automatically defeat the loss-of-faculties theory. The State may point to driving behavior, speech, coordination, instructions and responses, field sobriety evidence, admissions, or video. The defense can compare each observation with the complete record, including road and weather conditions, the reason for a movement, medical limitations, fatigue, footwear, the test surface, and whether the video supports the written report.
A number also must be understood in its own timeline. The stop, arrest, specimen collection, and laboratory or instrument analysis may happen at different times. A result is evidence, not a substitute for identifying which statutory theory is charged and whether the surrounding records support it.
Drugs, prescriptions, and combinations
Section 49.01(2) is not limited to illegal drugs. A prescription drug, an over-the-counter medication, alcohol combined with medication, or a combination of substances may be the alleged cause. Under section 49.10, being entitled to use the substance is not itself a defense.
That rule does not make prescription records irrelevant. The identified substance, prescribed dose, timing, refill history, reported concentration, metabolites, medical condition, and other substances can help evaluate whether the State can connect the substance to an alleged loss of normal faculties. The drug DWI page addresses that evidence in more detail.
Operating a motor vehicle in a public place
The offense requires more than intoxication. Section 49.04 requires operating a motor vehicle in a public place while intoxicated.
Operating is the statutory word
The statute does not limit DWI to a vehicle seen moving down a road. Vehicle position, the engine and controls, keys, witness accounts, admissions, surveillance video, and the sequence of events can bear on whether the person operated the vehicle.
Public place is broader than a public highway
Penal Code section 1.07 includes places to which the public or a substantial group has access. Streets and highways qualify, but so can common areas of schools, hospitals, apartment houses, office buildings, transport facilities, shops, and parking lots.
Under 21: DUI by a minor and DWI are different offenses
Texas DUI by a minor is the separate offense in Alcoholic Beverage Code section 106.041. It applies to a person younger than 21 who operates a motor vehicle or watercraft in a public place with any detectable amount of alcohol. It does not require proof of intoxication and is expressly not a lesser-included offense of DWI.
A minor may still be charged with full DWI under section 49.04 when the State alleges intoxication. The age, the detected substance, the alleged conduct, and the charging instrument identify which law applies. The underage DUI page explains the separate consequences.
CDL rules do not redefine the DWI offense
For a commercial driver, 0.04 is not a separate Texas Penal Code DWI charging threshold. It is a commercial-driver disqualification trigger for operating a commercial motor vehicle under Transportation Code chapter 522. A commercial driver can face that administrative consequence without the State proving the 0.08 numerical theory of DWI.
Any detectable alcohol while operating a commercial motor vehicle can also produce a 24-hour out-of-service order. A DWI conviction in a personal vehicle can still disqualify a commercial driver. The CDL and DWI page separates the criminal case from the commercial-license consequences.
Questions about intoxication evidence
Is 0.08 the only way Texas can prove intoxication?
No. The State may rely on an alcohol concentration of 0.08 or more, or on an alleged loss of normal mental or physical faculties caused by an introduced substance.
Does a valid prescription prevent a DWI charge?
No. Entitlement to use a substance is not a defense under section 49.10. Prescription, dosage, medical, and timing records can still be important when evaluating whether the substance caused an alleged loss of faculties.
Does a vehicle have to be on a public road?
No. The statute requires operation in a public place, a term that can include parking lots and other places accessible to the public or a substantial group.