9.4 Standardized Field Sobriety Testing

Standardized Field Sobriety Testing

Impaired-driving enforcement is one of the highest-stakes traffic missions in North Carolina. The 28-hour Standardized Field Sobriety Testing (SFST) block combines N.C.G.S. Chapter 20 DWI law with the NHTSA-standardized psychophysical battery. You must know both: the legal elements that make the offense, and the cognitive framework of the tests that help establish probable cause.

DWI Elements under N.C.G.S. § 20-138.1

Under § 20-138.1, a person commits impaired driving if the person drives any vehicle upon any highway, street, or public vehicular area in North Carolina:

Any one prong can sustain the offense. Legal entitlement to use alcohol or a drug is not a defense. Impaired driving under this section is a misdemeanor sentenced under § 20-179 after a required sentencing hearing. (For purposes of this section, "vehicle" does not include a horse.)

BLET scenarios often hide the "drives" or "public vehicular area" element — parking-lot and private-drive questions are testing whether you know PVA concepts, not whether you can recite 0.08 alone.

Implied Consent and Chemical Testing Themes

North Carolina's implied-consent scheme is centered on § 20-16.2 and related procedures in § 20-139.1:

• Consent by driving: Any person who drives a vehicle on a highway or public vehicular area gives consent to a chemical analysis if charged with an implied-consent offense (including impaired driving under § 20-138.1 and several related offenses).
• Officer authority: A law enforcement officer with reasonable grounds to believe the person committed an implied-consent offense may obtain a chemical analysis.
• Rights advisement: Before the evidentiary test, the person must be advised of implied-consent rights in the statutory form (consequences of refusal, etc.).
• Unconscious persons: If the person is unconscious or otherwise incapable of refusal, the officer may direct a blood sample or other effectively performed chemical analysis without the usual notification/request sequence.
• Evidence of refusal: Under § 20-139.1(f), refusal to submit to a chemical analysis or to perform field sobriety tests is admissible in criminal, civil, or administrative actions.

Distinguish preliminary roadside breath tests (often treated as investigative tools with different refusal consequences) from the evidentiary chemical analysis covered by implied consent after charging. Classroom materials and current agency policy control the exact PBT rules you will apply in the field — the exam concept is that implied-consent revocation machinery attaches to the formal chemical-analysis process under § 20-16.2.

Willful Refusal Consequences (Themes)

A willful refusal to submit to the required chemical analysis triggers civil/administrative license revocation consequences under § 20-16.2 (commonly taught as an immediate short-term revocation followed by a longer DMV revocation period — learn the durations emphasized in your current lesson plan). Refusal does not make the DWI charge disappear; it often strengthens the State's case because refusal evidence is admissible, and officers may still pursue blood draws with judicial authorization in appropriate cases (especially death/serious-injury contexts under Chapter 20 procedures).

SFST Battery: HGN, WAT, and OLS (Cognitive Level)

The standardized battery has three tests. Standardization means instruction, administration, and scoring follow NHTSA protocols — improvising the test destroys its validated meaning.

Critical cognitive rules:

• SFSTs are tools to develop probable cause, not a substitute for the statutory elements of § 20-138.1.
• Medical conditions, injuries, age, footwear, roadway slope, and wind can affect WAT/OLS — document limitations and do not overclaim.
• HGN requires proper stimulus height, distance, and pass timing; rushing invalidates the observation.
• SFST is both a skills topic (you must administer tests correctly) and a knowledge topic (you must explain what each clue means and how it supports impairment opinions).

Grossly Aggravating Factors and NC Sentencing Structure (High Level)

After conviction under § 20-138.1, § 20-179 requires a sentencing hearing. North Carolina uses a special DWI sentencing grid — not ordinary Structured Sentencing — built around grossly aggravating factors (GAFs), then ordinary aggravating/mitigating factors if no GAF applies.

Commonly tested grossly aggravating factors under § 20-179(c) include:

1. A prior conviction for an offense involving impaired driving within the statutory timing rules (notably within seven years before the offense date, with additional timing variants in the statute).
2. Driving while the license was revoked for an impaired-driving revocation.
3. Serious injury to another caused by the defendant's impaired driving.
4. Driving with a child under 18, a person with the mental development of a child under 18, or a disabled person unable to exit the vehicle unaided in the vehicle.

High-level structure trainees must recognize:

Ordinary aggravating factors (for the lower levels) include themes such as gross impairment or AC 0.15+, especially reckless driving, negligent driving leading to a reportable accident, and certain prior records. Mitigating factors pull toward Level Five. Exact fine and active-time ranges are statute-driven; the exam priority is knowing what a GAF is and how GAF count drives level selection.

Integrating Law and SFST on the Road

A complete DWI investigation flows: lawful stop or encounter → observations of impairment → SFST (when safe/appropriate) → arrest decision under § 20-138.1 elements → implied-consent advisement and chemical analysis → report that also captures any § 20-179 GAF facts (child in car, serious injury, known prior, DWLR-impaired). The 28-hour block exists because missing any link — bad SFST administration, skipped rights advisement, or ignored GAF evidence — weakens both the criminal case and public safety.