Transportation Code · §49.01

DWI Procedure

DWI Procedure is covered under §49.01 and tested on the TCOLE peace officer licensing exam.

To prove this offense, the State must establish each of the following elements: Two prongs of intoxication — either prong sufficient; (A) Loss of normal use prong — typically proved by FSTs, observations, behavior; (B) Per se prong — BAC 0.08 or more.

Elements you must prove

  • Two prongs of intoxication — either prong sufficient
  • (A) Loss of normal use prong — typically proved by FSTs, observations, behavior
  • (B) Per se prong — BAC 0.08 or more

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Worked examples

Worked example 1

SCENARIO. Driver suspected of DWI is arrested and provides a breath sample of 0.06. May the State still pursue DWI?

  1. No — must be 0.08+
  2. Yes — DWI may also be proved under the 'loss of normal use' prong of intoxication (§49.01(2)(A)) regardless of BAC; the BAC reading is one of two independent ways to prove intoxication Correct
  3. Only if blood follows
  4. Only if there is an injury
Why: Texas's DWI definition has two independent prongs: 'loss of normal use of mental or physical faculties due to alcohol/drugs/combination' OR 'BAC 0.08 or more.' Either alone supports DWI. A 0.06 result does not preclude DWI prosecution under the loss-of-normal-use prong.
Statute: Tex. Penal Code §49.01(2)

Statutory definitions for this topic

Intoxicated Tex. Penal Code §49.01(2)
(A) Not having the normal use of mental or physical faculties by reason of alcohol, a controlled substance, a drug, a dangerous drug, a combination, or any other substance; OR (B) having an alcohol concentration of 0.08 or more.
Alcohol concentration / BAC Tex. Penal Code §49.01(1); Tex. Transp. Code §522.103
(A) Number of grams of alcohol per 100 mL of blood; (B) per 210 L of breath; or (C) per 67 mL of urine. The 'per se' DWI threshold is 0.08; 0.04 for operators of commercial motor vehicles.