Driving while intoxicated is a felony offense. Texas Penal Code Section §49.01 describes an impaired driver as: "not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body."
By doing a breath, blood, or urine test establishes the Blood Alcohol Content (BAC). The alcohol content is the concentration of alcohol in grams per:
210 liters of breath;
100 milliliters of blood; or
(C) 67 milliliters of urine.
The Texas Penal Code Section §49.01 (2)(b) defines a person over the age of 21 years, having a blood alcohol concentration of 0.08% or more as intoxicated. DWI fatal crashes are most common in persons aged 21 - 25, according to the Texas Department of Transportation.