While you are probably familiar with the abbreviations DUI and DWI, it is not always apparent that the two have different applications—and they are not necessarily interchangeable under Texas law. When you are using the words in everyday conversation the difference is not likely to be important, as most people understand that they are talking about driving under the influence and driving while intoxicated. However, in the Texas justice system, there are several very important differences between the two.
Age and BAC
The charges of DUI and DWI differentiate by age, mostly. Texas has a zero-tolerance policy for under-aged drinking and driving. Anyone drinking before they reach the age of 21 and then drives may face charges for DUI, regardless of their alcohol level. If the blood alcohol concentration (BAC) is equal to or greater than 0.08%, even those under-aged can face the harsher DWI charges. A driver who is over the legal drinking age of 21 who is legally intoxicated while driving on a public road may be charged with DWI.
In this context, “intoxicated” does not mean simply having a drink. To be intoxicated, one must either:
...