Texas Blood Alcohol Limits by Driver Type

Texas law sets different blood alcohol concentration (BAC) limits depending on who is driving. For drivers 21 and older operating a regular passenger vehicle, the legal limit is 0.08 percent. Drivers under 21 face a zero-tolerance standard: any detectable BAC of 0.02 percent or higher is illegal. Commercial drivers holding a CDL have a stricter limit of 0.04 percent, regardless of age.

These limits explore to breath tests, blood tests, and urine tests. A BAC reading at or above the legal limit for your category creates what Texas law calls per se intoxication — meaning the state does not have to prove you were actually impaired, only that your BAC met or exceeded the threshold. You can still be charged with DWI even if your BAC is below the legal limit if an officer observes signs of impairment.

Key Takeaways

  • The legal BAC limit in Texas is 0.08 percent for drivers 21 and older, 0.02 percent for drivers under 21, and 0.04 percent for commercial drivers.
  • A BAC at or above the legal limit is enough for a DWI charge without proof of impairment, but you can be charged below the limit if an officer observes impaired driving.
  • Texas law measures BAC through breath, blood, or urine tests, and refusing a test carries separate penalties including automatic license suspension.
  • A first DWI conviction in Texas carries jail time, fines, and a mandatory driver's license suspension of at least 90 days.

How Texas Measures and Tests BAC

When an officer suspects impaired driving, they typically request a breath test first. In Texas, breath tests are usually performed on an Intoxilyzer — a machine that measures alcohol in your breath and estimates your BAC. If you refuse a breath test, the officer can request a blood test or urine test instead, though blood tests are more common because they are considered more accurate.

You have the right to refuse any test, but refusing carries automatic consequences separate from any DWI charge. A first refusal results in an automatic driver's license suspension of 180 days. A second refusal within ten years brings a two-year suspension. These suspensions happen through the Texas Department of Public Safety, not through a court conviction, and begin when ready after you are arrested.

If you do take a test and the result is at or above the legal limit, that result becomes evidence in any DWI case. You can request an independent test of the same sample, and you have the right to see the maintenance records and calibration history of any breath machine used.

DWI Charges and Penalties in Texas

A first DWI conviction in Texas is a Class B misdemeanor. Penalties include a jail sentence of at least 72 hours and up to 180 days, a fine of $2,000, and a mandatory driver's license suspension of 90 days. You will also be required to complete a DWI education program and may face an ignition interlock device requirement, which forces you to pass a breath test before the vehicle will start.

A second DWI within ten years is also a Class B misdemeanor but carries harsher penalties: 30 days to one year in jail, a fine up to $4,000, and a license suspension of 180 days to two years. A third DWI within ten years becomes a felony, with one to ten years in prison and a fine up to $10,000.

These are the criminal penalties. You will also face administrative penalties through the Texas Department of Public Safety, which can suspend your license separately from any court sentence. If you are under 21, any DWI conviction results in automatic license suspension until age 21, regardless of the criminal sentence.

Implied Consent and Your Right to Refuse

Texas has an implied consent law. By driving on Texas roads, you are considered to have consented to a breath, blood, or urine test if an officer has probable cause to believe you are driving while intoxicated. This does not mean you cannot refuse — you can — but refusal has legal consequences.

If you refuse a test, the officer must tell you that refusal will result in automatic license suspension and that your refusal can be used against you in court. The officer does not need a warrant to request a breath test, but they do need a warrant to take a blood sample without your consent. In practice, if you refuse a breath test, officers often seek a warrant for blood.

Refusing a test does not prevent a DWI charge. You can still be charged based on the officer's observations of impairment, failed field sobriety tests, or other evidence. The refusal straightforward means there is no BAC number in the case — which can actually help your defense in some situations, though it also triggers the automatic license suspension.

Field Sobriety Tests and Arrest

Before requesting a breath test, an officer typically asks you to perform field sobriety tests — standardized physical and mental exercises designed to detect impairment. The three most common are the horizontal gaze nystagmus test (following a pen with your eyes), the walk-and-turn test, and the one-leg stand test. These tests are voluntary, and you can decline to perform them.

Declining a field sobriety test does not prevent an arrest, but it does remove that evidence from the case. If you perform the tests and the officer believes you failed, that becomes part of the probable cause for arrest. An arrest for DWI does not require a conviction — only probable cause that you committed the offense.

After arrest, you are taken to a police station or jail for booking. At that point, the officer will again request a breath, blood, or urine test. This is the official test that produces the BAC result used in prosecution. The field sobriety tests and any breath screening done at the roadside are separate from this official test.

License Suspension and Administrative Hearings

When you are arrested for DWI in Texas, your driver's license is taken and you receive a temporary permit valid for 40 days. During this time, you can request a hearing with the Texas Department of Public Safety to contest the suspension. This hearing is separate from any criminal court case and happens in the administrative system.

At an administrative hearing, the focus is whether there was probable cause for the arrest and whether you refused or took a test. The hearing officer is not a judge but a hearing officer employed by the Department of Public Safety. If you lose the hearing, your license suspension takes effect after the 40-day temporary permit expires.

If you did not request a hearing within 15 days of arrest, the suspension becomes automatic. Even if you are later found not guilty of DWI in criminal court, the administrative suspension can still stand because the standards of proof are different — administrative suspension requires only a preponderance of the evidence, while criminal conviction requires proof beyond a reasonable doubt.

Frequently Asked Questions

Can I be charged with DWI if my BAC is below 0.08 percent?

Yes. Texas law allows DWI charges based on impairment alone, without any BAC reading. If an officer observes signs of impairment — slurred speech, poor coordination, failed field sobriety tests — you can be charged even if your BAC is 0.05 percent or lower. The legal limit is a threshold for per se intoxication, not a threshold for prosecution.

What happens if I refuse a breath test?

Your driver's license is automatically suspended for 180 days on a first refusal. You can request a hearing to contest the suspension, but you must do so within 15 days of arrest. Refusal also cannot be used as evidence of guilt in criminal court in Texas, though the fact that you refused can be mentioned.

Do I have to perform field sobriety tests?

No, field sobriety tests are voluntary. You can decline without legal penalty. However, declining does not prevent arrest if the officer has other probable cause, such as the smell of alcohol or erratic driving. Declining straightforward removes that evidence from the case.

What is the difference between a breath test and a blood test?

Both measure BAC, but blood tests are generally considered more accurate because they directly measure alcohol in the bloodstream. Breath tests estimate BAC based on the ratio of alcohol in breath to alcohol in blood. Blood tests require a warrant without consent, while breath tests do not.

Can a DWI conviction be expunged from my record in Texas?

A DWI conviction cannot be expunged in Texas. However, if you are arrested but not charged, or if you are charged but acquitted, you may be able to have the arrest record sealed. Speak with a criminal defense attorney about your specific situation, as the rules depend on the outcome of your case.