Driving while intoxicated (DWI) under Texas Penal Code 49.04 (PC) is a criminal offense committed when a person drives a vehicle on a public road while intoxicated by alcohol, drugs, or controlled substances, or has a blood alcohol concentration of 0.08 percent or more. The consequences of a DWI charge are serious and can lead to statutory penalties like loss of freedom and driving privileges.
Recognizing the distinction between misdemeanor and felony charges, the administrative process for license suspension, and the type of evidence that law enforcement can use to prove impairment is essential to understanding DWI laws in Texas. Understanding these legal procedures can help you protect your rights and prepare for the potential consequences of a DWI charge. Read along to learn what laws, procedures, and constitutional rights may apply to your case.
The Legal Definition of Driving While Intoxicated Under Texas Law
Under PC 49.04(a), you commit a DWI offense by driving or controlling a motor vehicle on a public road while intoxicated by alcohol, drugs, or a combination of both. These violations are prosecuted under a two-part statutory regime, half of which is based on measurable scientific limits and the other half on subjective observations of human behavior.
Either of these standards can be used to arrest and charge someone at any time during a routine traffic stop. Prosecutors do not have to prove that you caused an accident. They can only prove that your behavior was within certain types of impairment in Texas.
Statutory Threshold for Blood Alcohol Concentration (BAC)
The state’s most crucial definition of intoxication is a very precise calculation of your blood alcohol level. Under Texas Penal Code 49.01(2)(B), a person is considered intoxicated per se when their alcohol concentration reaches 0.08 or more. This number is derived from biological ratios, which are the concentration of alcohol in your body.
According to Penal Code 49.01(1), this concentration is the amount of alcohol in one hundred milliliters (100 ml) of blood, two hundred ten liters (210 L) of breath, or sixty-seven milliliters (67 ml) of urine.
The law assumes impairment if a chemical test indicates a level of alcohol at or above this concentration. The prosecution need not show that your driving was visibly affected. A completed offense is committed when this chemical level is detected if you were driving a vehicle in a public place.
Commercial driver’s license holders are subject to a lower per se alcohol limit of 0.04 percent under Texas Transportation Code 522.081(a). For drivers under 21, Texas law generally follows a zero-tolerance approach, making any detectable amount of alcohol an offense under Texas Alcoholic Beverage Code 106.041.
The exact ratios are very technical to measure and require law enforcement officers to use approved testing devices and adhere to strict procedural timelines to ensure that the results are admissible in court. You will need to speak with an experienced defense attorney who will examine the chemical records and determine if the state of Texas met these standards.
Loss of the Normal Use of Physical or Mental Faculties
The second part of the statutory definition of intoxication is not based on a specific mathematical concentration of alcohol. The definition of intoxication found in PC 49.01(2)(A) provides that a person is intoxicated if they are unable to use their mental or physical faculties normally. This loss shall be the result of a drug, alcohol, or controlled substance, or a mixture of these.
This standard allows an officer to make an arrest even if your blood or breath test result is less than 0.08 percent. The prosecution rests on the officer’s subjective observations and proves the loss of normal use. Common signs are bloodshot eyes, slurred speech, loss of balance, or erratic driving.
Initial roadside contact may involve tests designed to assess your physical coordination, balance, and ability to follow instructions. However, these tests can be subjective and may be affected by factors unrelated to alcohol or drug impairment.
Physical fatigue, medical conditions, natural differences in coordination, and anxiety during a stressful traffic stop may affect your performance and potentially be mistaken for signs of impairment.
The burden of proof is on the state to prove beyond a reasonable doubt that any degradation observed was due to a direct effect of an intoxicating agent. The term "normal use" is not mathematically defined by statute, so your baseline of coordination is a key area of your defense.
Your attorney can dispute the officer’s opinions by offering other explanations for your physical actions during the stop. This defense is crucial to avoid the subjective arrest becoming a permanent criminal conviction.
The Civil and Criminal Side of a Texas DWI Arrest
Driving under the influence is a double jeopardy offense: two separate cases are filed simultaneously. There are two separate processes to navigate: the criminal case in the county court and the administrative proceeding involving your driver’s license. Each process has its own rules, standards of proof, and procedures, so the outcome of one does not necessarily determine the outcome of the other.
The Criminal Prosecution Process in County Courts
The criminal track starts once you are arrested and booked. It is a judicial proceeding prosecuted by the state under state criminal authority. It requires the state to have a formal complaint filed under Tex. Code Crim. Proc. art. 15.04.
The state formally charges you and begins the required appearances. An arraignment is required, and you should enter an official not-guilty plea. After this, your case moves on to the pretrial discovery phase, where the prosecution will share all evidence they have against you.
Your defense attorney will request and review the arresting officer’s written report, dashcam video, body camera video, and any chemical test logs. Your lawyer may file a motion to suppress if the evidence is the result of a constitutional violation by the officer. This motion is to have the evidence excluded from the trial if it violates the law.
Pretrial negotiations with the Tarrant County District Attorney’s office are a crucial step in your case. Prosecutors may be willing to recommend a lesser charge (reckless driving) or a pretrial diversionary program, depending on the strength of your defense. If you cannot agree, your case will go to a formal trial.
In court, the prosecution must establish all elements of the crime beyond a reasonable doubt before a jury of 12 or a judge. Your criminal defense lawyer can help you throughout this complicated legal journey, safeguarding your rights and ensuring that the state meets its rigorous evidence requirements. Having professional defense representation from the outset can increase your chances of a dismissal or a favorable plea agreement.
The Civil Administrative License Revocation (ALR) Process and the Strict 15-Day Deadline
The second track is separate from your criminal case. If testing shows an alcohol blood concentration (BAC) that is 0.08 percent or more, the Public Safety department may take administrative action against your driving license under Texas Transportation Code 524.012. You may also face separate administrative consequences for refusing to provide a blood or breath specimen as required by Texas law.
You have to act quickly because the deadline to request an Administrative License Revocation (ALR) hearing is generally 15 days from the date you receive notice, as provided by Texas Transportation Code 724.035 and 524.011(b).
If you do not request an ALR hearing within the statutory deadline, your driver’s license may be suspended beginning on the applicable date following your arrest. A dismissal of the criminal DWI case does not necessarily prevent a separate administrative license suspension from taking effect. If you make a timely request for a hearing, the administrative suspension is generally stayed until the hearing is completed.
The Department of Public Safety is required to establish certain elements for the judge at the hearing. They are required to demonstrate that they had a reasonable suspicion for the stop and probable cause for your arrest. They also need to be able to demonstrate that you were asked for a specimen and you refused it or failed the test.
This administrative hearing is an important pretrial discovery tool for your defense lawyer. Your lawyer may request the police report and have the arresting officer appear in court to explain it, and may be able to find “weaknesses” in the state’s evidence.
Classification of Misdemeanor and Felony DWI Penalties in Texas
The consequences of an operating while intoxicated conviction increase dramatically depending on the circumstances and your criminal history.
Standard First and Second Offense Misdemeanor Penalties
Your first DWI charge is a misdemeanor classified as Class B in Texas. Under PC 49.04(b), a conviction will result in a fine of up to $2000 and a jail term of up to 180 days, according to PC 12.22. If police stop you and there is an open container of alcohol in your vehicle, you may face additional legal consequences. Under PC 49.04(c), a DWI conviction carries a minimum jail term of 6 days when an open bottle of alcohol is found in the passenger area of the vehicle.
Under Texas Transportation Code 521.344, your driver’s license may be suspended for 90 days up to 1 year, depending on the offense and applicable circumstances. In addition, Transportation Code 708.102 provides for a 3-year license suspension in certain cases involving a conviction for a driver’s license offense.
You may also face an annual surcharge of $1,000 to $2,000, which is separate from any court fines or other penalties. If arrested for the second time, PC 49.09(a) makes the offense a misdemeanor classified as Class A. Under PC 12.21, this could result in a fine of up to $4000 and a jail sentence of up to 1 year.
Under Tex. Transp. Code 521.344(a)(2), your license suspension period is extended from 180 days to up to 2 years. Additionally, Texas Code of Criminal Procedure Article 17.441 may require an IID (ignition interlock device) as a condition of bond or probation for certain repeat DWI offenses. When required, you are responsible for the cost of installing and maintaining the device.
To make matters easier to understand, Senate Bill 2320 of the 89th Texas Legislature would have made first-time DWIs Class A misdemeanors, but the bill failed to pass in committee on May 22, 2025, and the current misdemeanor ranges remain unchanged in 2026.
Felony Enhancements for Child Passengers and Multiple Prior Convictions
Texas law has certain aggravating factors that can raise a DWI charge from a misdemeanor to a felony. Under PC 49.045, a person commits a felony by driving a vehicle in a public place while intoxicated when a passenger in the vehicle is younger than 15 years old. The state does not have to prove that you were driving recklessly or that you injured children to obtain this felony enhancement.
A felony conviction results in a fine of up to $10,000 and a mandatory prison sentence of 180 days to 2 years in a state jail facility. Two or more previous DWI convictions on your criminal record will automatically result in the upgrade of any subsequent DWI.
Under PC 49.09(b), a third DWI offense may be prosecuted as a 3rd-degree felony when the required prior convictions are established. Texas law does not impose a general time limit on prior DWI convictions used for enhancement under this provision. As a 3rd-degree felony, the offense carries a potential fine of up to $10,000 and imprisonment for 2 to 10 years under PC 12.34.
You could also lose your driver’s license for up to 2 years, and the court will require an interlock device to be installed in any car you drive. Other consequences of felony convictions are harsh, such as loss of civil rights, limited job prospects, and a permanent criminal record.
Common Legal Defense Strategies to Challenge Impairment Evidence
To defeat state allegations, a systematic, scientifically supported defense is needed. Defense strategies focus on the structural integrity of the field investigations and the precise mechanical reliability of the chemical testing devices, revealing significant procedural flaws that often lead to the dismissal of the state’s case.
Questioning the Validity and Calibration of Chemical Testing Equipment
Chemical testing equipment used in an operating-while-intoxicated prosecution is a critical scientific tool that relies heavily on its accuracy. Breathalyzer devices (like the Intoxilyzer 9000 used across North Texas) do not measure the amount of alcohol in your blood.
Rather, they rely on infrared spectroscopy to detect alcohol vapors in your breath and then a mathematical formula to calculate your BAC. This estimate is very sensitive to external factors and technical errors.
If the prosecution relies on a breath test, the test should comply with applicable Texas laws and administrative requirements. Texas Transportation Code 724.016 addresses the administration of breath specimens, while Texas Administrative Code Title 37, Part 1, Chapter 19 contains requirements for breath-testing procedures and equipment.
These requirements include proper maintenance, calibration, and accuracy checks. Records showing that the device was not properly maintained or calibrated, failed required accuracy checks, or was operated by an unauthorized or improperly certified person may provide grounds to challenge the reliability or admissibility of the breath-test results.
Also, the breathalyzer results may change depending on your biological situation. Breath measurements can be inflated by acid reflux (also called GERD), diabetes, and dental products. This mechanical weakness does not mean that a reading of more than 0.08 percent is necessarily evidence of statutory intoxication.
Blood tests can also be subject to error. Blood samples should be collected by trained health professionals in a hygienic setting, in accordance with strict clinical protocols. Blood vials that are not inverted properly will prevent the chemical preservatives and anticoagulants from mixing, allowing the sample to ferment and leading to an artificially high alcohol level.
Your defense attorney should review the chain of custody, identify missing documentation, and examine how your specimen was collected, handled, and processed. An expert can evaluate the testing methods and identify errors that may undermine the reliability of the results. These issues may provide grounds to challenge or suppress the evidence.
Examining the Administration of Standardized Field Sobriety Tests
Standardized Field Sobriety Tests (SFSTs) are roadside tests built by the National Highway Traffic Safety Administration (NHTSA) to help officers assess possible impairment. The three standardized tests are the Horizontal Gaze Nystagmus, Walk-and-Turn, and the standing-on-one-leg technique.
Officers look for specific signs of impairment while scoring these tests. However, factors such as physical conditions, fatigue, balance problems, and the testing environment can affect your performance.
The Horizontal Gaze Nystagmus test is highly technical and involves involuntary eye movements that occur when your eyes track a stimulus. Federal guidelines require that officers maintain a certain distance and speed from the stimulus. Failure by the officer to follow these exact parameters results in a biologically invalid evaluation.
Tests that require physical balance (One-Leg Stand, walk, and Turn) involve complex physical instructions. You may not be able to do these exercises even if you are not intoxicated due to severe anxiety, fear, fatigue, or natural variations in coordination.
Your defense lawyer can question the officer in a systematic manner about how they grade their work, point out any deviations from the standard training manual, and show that your roadside performance was due to stress, medical conditions, or environmental factors, not intoxication.
Find a Fort Worth DWI Defense Lawyer Near Me
If you are facing a DWI charge in Texas, you need to take immediate steps to ensure that you do not lose your driver’s license and face severe criminal penalties. DWI cases are both criminal and administrative, and there is only a 15-day window to challenge the suspension. At Fort Worth DWI Defense Lawyer, our defense attorneys are ready to protect your rights, challenge unreliable chemical tests, and fight for the best possible outcome in your case.
Our attorneys have a wealth of experience in criminal defense and are familiar with the procedures of the courts in Fort Worth and the Texas DWI laws. We can help you understand the options available to you and build a defense strategy that is right for your case. If you are charged with impaired driving, do not delay in getting legal advice. Contact us today at 817-470-2128 for a private consultation.
