DWI Legal BAC Limit in San Antonio, Texas: What you need to know.
If SAPD or the Bexar County Sheriff’s Office arrested you for a DWI in San Antonio, then the first thing you probably saw on your paperwork was decimal point: .08. While Texas laws says this is the legal limit, a BAC result does not lead to an automatic conviction.
At the Law Office of Genaro R. Cortez, PLLC, we represent motorists facing DWI charges in San Antonio who have been “caught in the splash zone of innocence”–those cases where the science is shaky and the legal limit is up for debate.
What is the legal BAC limit in Texas?
In Texas, the legal limit for Blood Alcohol Concentration is .08%. Under this “per se” theory of DWI, the law considers a driver legally intoxicated if her BAC is .08 or greater when she was driving.
However, there are different standards for different types of drivers in San Antonio:
- Adult drivers (21 and over): .08% BAC.
- Commercial Drivers (CDL): .04% BAC.
- Minors (Under 21): Any detectable amount of alcohol.
Notably, the age limit of the driver distinguishes the crimes of DWI and DUI in Texas. For example, police will charge a minor with any amount of alcohol in his system with DUI. In contrast, police will charge an adult with DWI if his BAC is .08% or higher.
The “Time Gap” problem: Driving vs. Testing.
A common issue in San Antonio DWI cases is the time gap between the initial traffic stop and the actual breath or blood test.
The law requires you to be intoxicated at the time you were driving, not at the time of the test. Whether you are pulled over on I-10 or 1604, it often takes 45 minutes to two hours before a sample is taken. If your BAC was .09 at the station, then it may have been well below .08% when you were behind the wheel.
In short, you may be able to argue the rising BAC defense. That is to say, you were below the limit when you were arrested, but it rose by the time police tested your breath or blood.
Texas Implied Consent & “No Refusal” Weekends.
Texas Implied Consent laws mean that by driving on San Antonio roads, you agree to give police a breath or blood sample if they arrest you for a DWI in San Antonio, Texas.
Moreover, DPS will suspend your driving privileges as follows:
- Refusal: If you refuse, then DPS can suspend your license for 180 days.
- Failure: If you provide a sample over .08, then DPS may suspend your license for 90 days.
Note: “No refusal” weekends are now permanent in Bexar County, Texas. In other words, if you decline to provide a breath sample, then the police will get a search warrant to draw your blood. And they can do this any day of the week in San Antonio, Texas.
DWI in San Antonio During the Holidays.
San Antonio and Bexar County police crackdown on DWI and DUI drivers during the following holidays:
- New Years Eve.
- Fiesta Events.
- Memorial Day Weekend.
- Labor Day Weekend.
- Thanksgiving.
- Christmas.
During these holidays, local officials put extra police on patrol to arrest suspected drunk drivers.
From there, police send the file to the Bexar County District Attorney’s Office, which will then prosecute the motorist for DWI. Additionally, county or district clerk will randomly assign your case to a county or district court judge at the Cadena-Reeves Justice Center.
Fighting the Science: Blood vs Breath Tests in San Antonio, Texas.
As a San Antonio DWI defense attorney, I look for technical errors in how the nurse or police took your blood samples.
DWI Blood Draws and Contamination.
The nurse draws your blood into vials that have sodium fluoride (NaF). This chemical prevents your blood from fermenting. Nevertheless, blood draws cause known problems:
- Improper Mixing: If the nurse does not invert the vial 8-10 times, the chemicals won’t mix properly. This causes clotting.
- Candida Albicans (Yeast): This common yeast can combine with sugar in a blood vial to create “new” alcohol inside the tube, leading to a falsely high BAC result.
The Intoxilyzer 9000.
Texas uses the Intoxilyzer 9000 for breath testing. This machine uses infrared technology to identify the “fingerprint” of an ethanol (alcohol) molecule in your breath sample. While sophisticated, it cannot account for the “rising alcohol defense.”
The Rising Alcohol Defense.
Alcohol consumption follows a curve with three key points: Absorption, Peak, and Elimination. Your BAC depends on where you are on this curve. If you are still absorbing alcohol when you are tested, then your BAC result will be higher than it was when you were driving. On the other hand, if you are in the elimination phase, then your BAC result when tested can be either higher or lower than when police pulled you over.
Factors that distort the BAC curve include:
- Food in the stomach (and the type of food.)
- Your weight and gender.
- The time period of drinking.
- Your body’s specific elimination rate (commonly cited as .015/hour by labs, though this varies from person to person.)
To summarize, a DWI arrest is not as simple as having a BAC result that is over the limit. An experienced San Antonio DWI Defense Attorney can help you with these issues and help you make the best decisions for your case.
Facing a DWI in San Antonio? Don’t Settle.
If your BAC test resulted in a .09, .10, or .11, then you are in the “trial zone.” If you look good on the arrest video and the science is questionable in your case, then have a fighting chance at a not guilty verdict.
Do not let a single number define your future. Whether your case involves a first-time DWI or a complex blood draw warrant, you need a solo practitioner who understands the local San Antonio courts and the technicalities of BAC Science.
Where we defend DWI cases.
- Bexar: (San Antonio, the Pearl/Midtown, South Town, Stone Oak, Alamo Heights, Leon Valley, Monte Vista, Terrell Hills, and Downtown.)
- Atascosa: (Jourdanton, Pleasanton, Poteet, and Lytle.)
- Kendall: (Boerne.)
- Medina: (Hondo.)
- Uvalde: (City of Uvalde.)
Can I fight a .08 BAC result in San Antonio?
Yes. A .08 BAC is not an automatic conviction. We challenge results based on the “Rising Alcohol” defense, improper blood vial mixing, and yeast contamination (Candida Albicans) which can falsely inflate BAC levels.
How long does a DWI license suspension last in Texas?
If you fail a breath test, your license can be suspended for 90 days. If you refuse the test, the suspension is 180 days. You only have 15 days from your arrest to request an ALR hearing to fight this suspension.