Driving While Intoxicated or Driving Under the Influence in Texas is a serious crime with severe penalties if convicted. The repercussions of this charge can impact your life for many years. In the State of Texas, it is illegal to operate a motor vehicle with a blood alcohol concentration (BAC) of .08 percent. This is the benchmark for an impaired driver that is used throughout the United States. The limit for commercial drivers is .04 percent and .02 percent for drivers under the age of 21. It is also illegal to drive while under the influence of marijuana, cocaine, inhalants and other intoxicants. If you are charged with this offense, your best option is to contact an experienced DWI attorney to defend you.