In Texas, a person can be arrested for a DWI if their blood alcohol concentration (BAC) is .08% or higher. A DWI, or driving while intoxicated, is a drunk driving conviction is above the state legal alcohol limit, rendering the driver legally impaired. A DUI conviction is reserved for drivers under 21 who are drinking illegally. The legal limit in Texas is as follows: Standard, non-commercial drivers: 0.08 Commercial drivers: 0.04 Drivers under 21: 0.01 Penalties, Fines, & Suspension Texas DWI & DUI Penalties, Fines,