In this article, you’ll learn the legal alcohol limit for regular, commercial, and underage drivers in the State of Texas. We’ll discuss how police measure the amount of alcohol in your system, as well as an estimate of how much alcohol can be consumed to reach those limits.

Blood Alcohol Concentration for Legal Driving in Texas

As with most states in the union, in Texas, operating a vehicle with an alcohol concentration of 0.08+% in your blood is illegal. If a law enforcement officer catches you driving a car, truck, motorcycle, boat, or other heavy machinery with a blood alcohol level greater than 0.079%, you can be arrested for Driving While Intoxicated, which is a Class B misdemeanor that requires jail time and a temporary suspension of your driving privileges.

Legal Alcohol Limit for Truck Drivers

As you might imagine, the drunk driving laws are stiffer for commercial drivers. They are considered to be driving intoxicated with a blood alcohol content of 0.04+%. Furthermore, if someone with a CDL gets convicted of a DWI in their personal vehicle off-the-job, this can result in the Federal Motor Carrier Safety Administration suspending their commercial driving privileges as well as their regular driving privileges.

Legal Alcohol Limit for Drivers Under 21 

Texas does allow people under 21 to consume alcohol in the presence of their parents, but generally speaking, it’s illegal to consume alcohol if you’re underage. Because of this, there is zero tolerance for any alcohol consumption whatsoever for drivers under 21. To be clear, a blood alcohol level of 0.001% could theoretically lead to a DWI for a 20-year-old driver in Texas. 

Measuring Blood Alcohol Content

The police use two main methods for testing a driver’s blood alcohol content (BAC): breathalyzer and blood test. A breathalyzer device measures the alcohol content in the air exhaled by the driver, which correlates to the amount of alcohol in the driver’s bloodstream. 

Breathalyzers give an estimate of the BAC and are less reliable. Blood tests are very accurate, but because they are invasive, the police should obtain a search warrant before administering a blood test to determine BAC. The police will often administer a breathalyzer test, and if the results indicate intoxication, they will use that as grounds to obtain the search warrant for the blood test.

Assessing Your Own Blood Alcohol Content

Three different people can drink and eat the exact same thing over the course of an hour and end up with three very different BAC levels. Here are just a few variables that impact one’s blood alcohol level:

• Weight/body type
• Fat content
• Muscle content
• Metabolism
• Emotional well-being/mood
• How quickly drinks were consumed
• How strong the consumed drinks were
• If what you drank was carbonated
• Medications taken
• What you did or did not eat
• How hydrated you were before consuming the alcohol
• Gender
• Age
• Overall alcohol tolerance and health

With all of these variables, it’s very difficult for a driver to truly know whether she or he is over 0.08%. We do not recommend relying on online BAC calculators and charts because there are simply too many variables to account for. We also do not recommend relying on the “one drink an hour” adage. Generally speaking, if you are slurring your speech, undergoing rapid mood swings, feeling sleepy or forgetful, wobbly/falling over, or making poor decisions, you should assume that you are too drunk to drive. It is always better to be safe than sorry.

But I Was Under the Limit

You can still be arrested for DWI if your BAC is below the legal limit. Again, considering the myriad of variables affecting how alcohol impairs people, someone can be swerving all over the road, fail a field sobriety test, reek of alcohol, and still be below 0.08%. If this is the case, an arrest may well be warranted, and the charge can stick.

Reach Out to an Austin, TX Criminal Defense Lawyer 

Were you arrested for a DWI? The Law Office of David D. White can help! We are passionate about defending you and protecting your rights. We are knowledgeable and experienced Austin, TX, criminal defense lawyers. Book a no-cost consultation with David or Kenneth now!