Can a driver be charged with DWI in a parking lot?

You may be surprised to learn that the answer to this question is: YES.

Texas Penal Code Sec. 49.04(a) sets out the elements of the criminal offense of Driving While Intoxicated and reads as follows:

(a) A person commits an offense if the person is intoxicated while operating a motor vehicle in a public place.

Under Texas law intoxicated means: (a) 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 in the body; or (b) having an alcohol concentration of 0.08 or more.

So in the case of a privately owned parking lot that is accessible and used by the public, if a person is operating a motor vehicle while intoxicated, that person can be charged with DWI.