A knowledgeable criminal defense lawyer will be able to identify and assert any applicable defenses to a DUI/DWI charge. These defenses generally have a narrow application to specific facts and circumstances and might include (1) an improper stop of the motor vehicle; (2) field sobriety tests were improperly administered; (3) improper interrogation of the defendant (generally only applies after the defendant is arrested); (4) breath tests (portable breathalyzer in the field and standard breathalyzer at the police station) were not properly administered or the breathalyzer machines were not properly calibrated and maintained; (5) blood test was not properly administered and the chain of custody (handling) of the blood sample was improper and unreliable; (6) due to rising blood alcohol concentration, the defendant’s BAC was below the legal limit when the defendant was stopped, and rose to a higher level when the defendant subsequently provided a breath or blood sample (after a lapse of time of an hour, for example); and (7) the defendant has medical conditions or is on medication that affected breath, blood, or field sobriety tests.

There may be other facts and circumstances that give rise to a defense that may be asserted to a DUI/DWI charge. The best defense, of course, is not to drink and drive. And the second-best defense may be to refuse to provide evidence that may incriminate yourself—by politely (1) declining to answer police questions, (2) declining to participate in field sobriety tests, (3) declining to provide a breath or blood sample, and (4) asking to speak to a lawyer.

State Statutes for the State of Texas

Federal Statutes