NC Cannabis DUI & Driving Laws

Last verified: April 2026

The Statute: N.C.G.S. § 20-138.1

NC’s Driving While Impaired (DWI) statute, N.C.G.S. § 20-138.1, makes it unlawful for any person to drive a vehicle on a highway, street, or public vehicular area while:

1. Under the influence of an impairing substance;
2. After having consumed sufficient alcohol that the person has, at any relevant time after the driving, an alcohol concentration of 0.08 or more; or
3. With any amount of a Schedule I controlled substance or its metabolites in blood or urine.

Marijuana is classified as Schedule VI under N.C.G.S. § 90-94 — not Schedule I — so cannabis DWI cases proceed under the impairment theory, not under any per se metabolite rule. There is no per se THC blood-level limit in NC law, and the prosecution must prove actual impairment beyond a reasonable doubt.

A person commits the offense of impaired driving if he drives any vehicle upon any highway, any street, or any public vehicular area within this State (1) while under the influence of an impairing substance; or (2) after having consumed sufficient alcohol that he has, at any relevant time after the driving, an alcohol concentration of 0.08 or more.

N.C.G.S. § 20-138.1 — Impaired Driving

How Cannabis DWI Cases Are Built

Because there is no per se THC threshold, cannabis DWI prosecutions in NC depend on observational and procedural evidence. A typical investigation involves:

1. Initial stop — based on a traffic violation or driving behavior. The smell of marijuana from the vehicle has historically been treated as probable cause for further investigation in NC, though that doctrine is being tested as legal hemp products produce identical odors.
2. Standardized Field Sobriety Tests (SFSTs) — the three-test battery (Horizontal Gaze Nystagmus, Walk and Turn, One-Leg Stand) was developed and validated for alcohol impairment, not THC, but it is still administered.
3. Drug Recognition Expert (DRE) evaluation — the NC State Highway Patrol participates in the IACP-administered DRE program. A DRE-certified officer conducts a 12-step protocol including vital signs, eye examinations, divided-attention tests, and a structured interview.
4. Chemical testing — a blood draw or urine sample under the implied-consent statute. THC blood levels are reported but are not dispositive of impairment in NC.

Implied Consent — N.C.G.S. § 20-16.2

Under NC’s implied-consent statute, every person who drives on a NC roadway is deemed to consent to a chemical analysis if charged with an implied-consent offense. N.C.G.S. § 20-16.2 requires officers to read the driver a written notice of rights before the test. Refusal to submit triggers an automatic 12-month civil license revocation by the NC Division of Motor Vehicles, separate from any criminal penalty.

The implied-consent rule applies whether the substance at issue is alcohol or a drug. A driver suspected of cannabis DWI who refuses a blood draw faces the same 12-month DMV revocation as a driver who refuses a Breathalyzer for alcohol. Police can also seek a search warrant for a blood draw following refusal, and warrant-based draws are routine in major counties.

The Five-Level Punishment Grid

NC sentences DWI under a five-level grid, codified at N.C.G.S. § 20-179. The court determines the level by counting grossly aggravating factors, aggravating factors, and mitigating factors developed at sentencing.

Grossly aggravating factors include a prior DWI conviction within seven years, driving with a license revoked for impaired driving, serious injury caused by the impaired driving, and driving with a child under 18 in the vehicle. Most cannabis-only DWI cases without a prior record settle at Level 4 or Level 5, but the presence of a child or a prior conviction can rapidly escalate exposure.

License Suspension

A first DWI conviction triggers a one-year license revocation. A second conviction within three years triggers a four-year revocation, and a third within five years triggers permanent revocation under § 20-19. The 12-month civil revocation for refusal under § 20-16.2 runs separately and can stack with criminal revocations.

Limited driving privileges are available under § 20-179.3 for first-offense DWIs at most levels, allowing for work, school, and treatment trips during the revocation period. Conditions typically include enrollment in a substance-abuse assessment program (the ADETS course or a longer treatment program depending on assessment results) and an ignition interlock device for cases involving alcohol concentrations of 0.15 or more.

Driving With a Passenger’s Cannabis

Cannabis discovered in the vehicle — even if no impairment is established — is a separate possession offense, charged against the driver, the passenger, or both depending on knowledge and control. Constructive-possession doctrine in NC permits the State to charge a driver who has knowledge and control of cannabis in the vehicle, even when it is physically in a passenger’s pocket or bag.

A driver returning from the Cherokee dispensary with legally purchased cannabis in the car is in possession the moment the vehicle leaves the Qualla Boundary. The on-Boundary purchase is irrelevant to NC charging decisions once the product crosses into state jurisdiction.

Hemp, Delta-8, and DWI

Legal hemp products containing Delta-8, Delta-9 (within the 0.3% dry-weight federal limit), THCA, and HHC are intoxicating. Driving impaired by legal hemp products is still a violation of § 20-138.1. The statute reaches any “impairing substance,” not only Schedule VI controlled substances. Drivers should treat legal hemp products like alcohol or any other impairing substance for purposes of operating a vehicle.

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