Dallas DWI Attorneys

The Forensic Defense in Dallas BWI Cases

SFST validity on water. Texas law enforcement officers conducting BWI investigations may administer both the standard Standardized Field Sobriety Tests (HGN, walk-and-turn, and one-leg-stand) and the separate marine-specific field sobriety test battery developed by NHTSA for the boating enforcement context, which includes Romberg Balance, Finger to Nose, and Hand Pat in addition to adapted versions of the walk-and-turn and one-leg-stand. Both batteries have their own administration protocols, and deviations affect the validity of the results. Extended time on a vessel also produces a phenomenon known as “mal de débarquement” (a persistent sense of motion after leaving a boat) that can affect balance and gait performance on tests administered immediately after docking, regardless of which battery was used. Deandra Grant is a trained SFST instructor and challenges the administration, scoring, and interpretation of both the land-based and marine-specific tests in every BWI case.

HGN and environmental factors.  The Horizontal Gaze Nystagmus test requires precise administration under controlled conditions. Sun glare, wind, fatigue from outdoor activity, and the residual motion effects of boating are all factors that can affect HGN performance independent of alcohol consumption. Whether the Game Warden administering the test accounted for these conditions, and whether the test was properly administered under the NHTSA protocol, is examined in every case.

Texas Game Warden procedures.  BWI stops in the Dallas area are typically conducted by Texas Game Wardens, not municipal police officers or DPS troopers. The legal standards governing a Game Warden’s authority to stop and board a vessel, conduct a safety inspection, and develop reasonable suspicion of intoxication are distinct from the traffic stop framework. The legality of the initial contact and any subsequent investigation is examined before any other defense strategy is built.

Chemical testing.  As in DWI cases, breath and blood test results in BWI cases are subject to challenge on the basis of testing methodology, instrument calibration, chain of custody, and the qualifications of the analyst. The ACS-CHAL Forensic Lawyer-Scientist credentials held by Deandra Grant and Douglas Huff allow for independent evaluation of the State’s chemical evidence at the chemistry level.

Article 38.23.  Texas’s exclusionary rule carries no good faith exception. The lawfulness of the Game Warden’s stop, boarding, and investigation is examined in every BWI case. Evidence obtained through an unlawful stop or search is suppressible under Article 38.23 regardless of what the evidence shows.

Why Deandra Grant Law for Dallas BWI Defense

• Trained SFST Instructor — Deandra Grant.  
• ACS-CHAL Forensic Lawyer-Scientist — Deandra Grant and Douglas Huff.  Chemical testing, breath and blood analysis, and the forensic evidence underlying the State’s case evaluated at the scientific level.
• Master of Science in Pharmaceutical Science + Graduate Certificate in Forensic Toxicology.  Blood alcohol analysis, retrograde extrapolation, and the pharmacology of alcohol impairment.
• 30+ years defending DWI and BWI charges in North Texas.  500+ trials to verdict.
• 17 published law books.  Including The Texas DWI Manual.
• Texas Super Lawyer since 2011.  AV® Preeminent rated by Martindale-Hubbell®.

If you are facing Boating While Intoxicated charges in the Dallas area, call (214) 225-7117 for a free, confidential consultation. Or schedule online at texasdwisite.com.