6.7 DWI, Implied Consent, SFST, and Chemical Tests
Key Takeaways
- BPOC Chapter 23 requires successful completion of the current NHTSA Standardized Field Sobriety Testing (SFST) course; the battery is the HGN, walk-and-turn, and one-leg stand.
- Texas DWI is operating a motor vehicle in a public place while intoxicated—loss of normal faculties OR a blood/breath alcohol concentration of 0.08 or more (Penal Code 49.04/49.01).
- Transportation Code Chapter 724 supplies implied consent, the statutory warning before a specimen request, refusal limits, and the officer's license-suspension and refusal-report duties.
- After refusal, a nonconsensual blood draw generally requires a search warrant (per Missouri v. McNeely and Section 724.012) unless probable cause plus genuine exigent circumstances exist.
Defining DWI and the SFST Battery
BPOC Chapter 23's goal is to detect, apprehend, and arrest the intoxicated driver. Objective 23.1 requires successful completion of the current National Highway Traffic Safety Administration (NHTSA) Standardized Field Sobriety Testing (SFST) course.
Texas Driving While Intoxicated (DWI) under Penal Code 49.04 is operating a motor vehicle in a public place while intoxicated. Penal Code 49.01 defines intoxicated two ways: (1) not having the normal use of mental or physical faculties due to alcohol, a drug, or a combination; or (2) a blood or breath alcohol concentration of 0.08 or more. Either prong proves the case—officers do not need both.
The Three Standardized Tests
| SFST component | What it measures | Standardized clues |
|---|---|---|
| Horizontal Gaze Nystagmus (HGN) | Involuntary eye jerking | 6 clues (3 per eye) |
| Walk-and-Turn | Divided attention, balance | 8 clues |
| One-Leg Stand | Balance, divided attention | 4 clues |
SFST items are standardized-process questions. The local BPOC source does not reproduce the full NHTSA manual, so know the structure and the discipline: proper administration in the prescribed manner, accurate observation, and accurate documentation. Deviating from standardized administration undercuts the validity of the clues.
Implied Consent and the Warrant Rule
Transportation Code Chapter 724 governs implied consent: anyone who operates a motor vehicle in a public place is deemed to have consented to a breath or blood specimen if arrested for DWI. BPOC lists its threads: applicability, consent to a specimen, taking of a specimen, refusal limits and exceptions, incapacitated persons, information provided before requesting a specimen (the statutory warning), breath and blood specimens, test results, additional analysis, the refusal statement, and the officer's license-suspension and written-refusal-report duties.
The Investigative Sequence (memorize the order)
- Stop — reasonable suspicion from driving facts (weaving, wide turns, near-misses).
- Observation — odor, slurred speech, bloodshot eyes, poor balance, admissions.
- SFST — standardized battery, properly administered and documented.
- Arrest — probable cause that the driver is intoxicated.
- Statutory warning (DIC-24) — read consequences before requesting a specimen.
- Specimen request — breath or blood.
- Refusal handling and documentation — license suspension paperwork.
The Critical Warrant Rule
After the U.S. Supreme Court's Missouri v. McNeely (2013), the natural dissipation of alcohol does not by itself create an exigency justifying a warrantless blood draw. Texas conformed: under Section 724.012, if a driver refuses a voluntary specimen, the officer may proceed only with a search warrant or with probable cause to believe genuine exigent circumstances exist. BPOC therefore directs officers to obtain a blood search warrant for a nonconsensual specimen rather than relying on the mandatory-specimen statute alone.
Forms and Traps
| Form | Use |
|---|---|
| DIC-23 | Notice of suspension / temporary driving permit |
| DIC-24 | Statutory warning read before the specimen request |
| DIC-25 | Peace officer's sworn report |
| THP-51 | Mandatory/blood-draw documentation |
Traps: (1) believing implied consent alone authorizes a forced draw after refusal—it does not; (2) forgetting the Administrative License Revocation (ALR) paperwork after a refusal; (3) blending the evidence categories. Keep them separate: driving facts support the stop, observations support suspicion, SFST supports the arrest decision, and Chapter 724 warnings and forms support the specimen and license process.
Mandatory Specimens, ALR, and DWI Levels
Section 724.012 also lists mandatory-specimen situations where the statute directs the officer to take a specimen—for example, when the DWI arrest arises from a crash that caused death or serious bodily injury, or when the driver has prior DWI-related convictions. But after Missouri v. McNeely (2013), the mandatory-specimen statute does not by itself override the Fourth Amendment: if the driver refuses, the officer still needs a warrant unless genuine exigent circumstances exist. BPOC's bottom line is to obtain a blood search warrant for any nonconsensual draw rather than relying on the mandatory statute alone.
Administrative License Revocation Runs in Parallel
A DWI arrest triggers two tracks. The criminal case proceeds under Penal Code Chapter 49. The Administrative License Revocation (ALR) track is civil and automatic: a driver who refuses a specimen, or who provides one showing 0.08 or more, faces license suspension independent of the criminal outcome. The officer's paperwork drives ALR—the DIC-23 notice of suspension/temporary permit, the DIC-24 statutory warning, and the DIC-25 sworn report. Forgetting this paperwork after a refusal is a classic exam miss.
| Outcome | Common first-offense ALR suspension |
|---|---|
| Refused a specimen | 180 days |
| Provided specimen ≥ 0.08 | 90 days |
DWI Severity Levels
| Level | Trigger |
|---|---|
| Class B misdemeanor DWI | First offense, BAC ≥ 0.08 or loss of faculties |
| Class A misdemeanor (DWI 0.15+) | BAC of 0.15 or more at testing |
| DWI with child passenger | State jail felony; passenger under 15 |
| Intoxication assault / manslaughter | Serious bodily injury / death caused while intoxicated |
Pulling It Together
The intoxicated-driver case is won by keeping the evidence streams separate and the sequence clean: articulable driving facts justify the stop; observed impairment plus a properly administered NHTSA SFST battery builds probable cause; the arrest precedes the DIC-24 warning; the specimen request follows; and a refusal triggers warrant analysis plus ALR paperwork. Mix those steps—reading the warning before arrest, forcing a draw on implied consent alone, or dropping the ALR forms—and the exam scenario is scored wrong even when the officer's instinct that the driver was drunk is correct.
A driver arrested for DWI refuses to give a breath or blood specimen. Under Section 724.012 and Missouri v. McNeely, how may the officer obtain a blood specimen?
Under Penal Code 49.01, which proof, standing alone, establishes that a driver was intoxicated?
Which Texas form is the statutory warning an officer reads before requesting a breath or blood specimen?
Which course must a cadet complete to satisfy BPOC Chapter 23 objective 23.1?