Tessmer Law Firm, PLLC brings you facts about DWI: Fact #1: In Texas, driving while intoxicated (DWI) means drunk driving, and the state uses your blood alcohol concentration (BAC) to determine whether you're too intoxicated to operate a motor vehicle. The State’s BAC limits are:  21 years old or older: 0.08%  Commercial drivers: 0.04%  Younger than 21 years old: Any detectable amount. Alcohol can affect you based on the number of drinks you’ve had, your body weight, and even your gender. Check out the TX blood alcohol percentage charts to learn more.