Cannabis & Driving in Ohio — 2 ng/mL OVI Guide

Ohio's 2 ng/mL Per Se Limit: The Lowest in the Nation

Ohio sets its per se THC threshold at 2 nanograms per milliliter (ng/mL) of blood. This is the lowest legal THC driving limit of any state in the country. For context, Colorado and Washington set their limits at 5 ng/mL — more than double Ohio's threshold.

A "per se" law means that if your blood contains THC at or above the legal limit, you are automatically in violation regardless of whether you appear impaired. You can be convicted of OVI even if:

You consumed cannabis hours before driving
You do not feel impaired
You pass field sobriety tests
Your driving behavior was perfectly normal

At 2 ng/mL, a single session of cannabis use can leave you over the legal limit for 24 hours or more. Regular users may exceed this threshold for days.

2 ng/mL Is Extremely Low

To put Ohio's limit in perspective: a single puff of cannabis can push blood THC above 2 ng/mL for 6–24 hours in occasional users. Regular users may never drop below 2 ng/mL. This is the strictest cannabis driving law in any legal state.

Four Types of Cannabis OVI in Ohio

Ohio law defines multiple pathways to a cannabis OVI charge. Understanding all four is critical:

1. Per Se THC (Active THC in Blood)

Blood THC at or above 2 ng/mL. No impairment evidence needed. This is the primary charge most cannabis consumers face.

2. Per Se THC Metabolite (Blood)

THC metabolite (THC-COOH, the inactive breakdown product) at or above 50 ng/mL in blood. THC metabolites can remain in blood for days or weeks after use, meaning you could be charged long after any impairment has passed.

3. Per Se THC Metabolite (Urine)

THC metabolite at or above 35 ng/mL in urine. Urine metabolites can persist for weeks or even months in heavy users. This means a frequent cannabis consumer could test positive for OVI even after weeks of abstinence.

4. Impairment-Based OVI

Even if your THC levels are below all per se thresholds, you can still be charged with OVI if an officer determines you are impaired. Drug Recognition Expert (DRE) evaluations, field sobriety tests, and behavioral observations can support this charge.

OVI Penalties

First Offense

Fine of $375–$1,075
3 days in jail (mandatory minimum) or 3-day driver intervention program
License suspension of 1–3 years
Possible ignition interlock device and restricted license plates
Mandatory substance abuse assessment

Second Offense (within 10 years)

Fine of $525–$1,625
10 days in jail (mandatory minimum)
License suspension of 1–7 years
Mandatory ignition interlock device
Restricted license plates
Vehicle immobilization or forfeiture possible

Third Offense (within 10 years)

Fine of $850–$2,750
30 days in jail (mandatory minimum)
License suspension of 2–12 years
Vehicle forfeiture possible
Felony charges possible depending on circumstances

SB 55: Pending Legislation

SB 55 has been introduced in the Ohio Legislature to potentially reform cannabis OVI standards. If passed, it could adjust the per se thresholds or how metabolite testing is handled. As of March 2026, SB 55 has not been enacted and the 2 ng/mL per se limit remains in full effect. Monitor legislative developments but do not rely on pending changes.

Medical Card Is Not a Defense

Holding an Ohio medical cannabis card does not protect you from OVI charges. Ohio's per se limits apply equally to medical patients and recreational consumers. If your blood THC is at or above 2 ng/mL, you can be charged regardless of your medical status.

How Impairment Is Detected

Ohio law enforcement uses a combination of methods to detect cannabis-impaired driving:

Traffic stop observations: Odor of cannabis, bloodshot eyes, slowed responses, or erratic driving may prompt further investigation.
Field sobriety tests: Standard tests (walk-and-turn, one-leg stand, etc.) can indicate impairment but are not specific to cannabis.
Drug Recognition Experts (DREs): Officers specially trained to identify drug impairment through a 12-step evaluation process.
Blood or urine testing: If officers suspect impairment, they can request a blood or urine sample. Ohio's implied consent law means refusing a test triggers automatic license suspension.

How Long Should You Wait to Drive?

Given Ohio's 2 ng/mL threshold — the lowest in the nation — standard impairment timelines are dangerously insufficient:

Occasional users: Blood THC can remain above 2 ng/mL for 12–24+ hours after a single session.
Regular users: Blood THC may stay above 2 ng/mL for several days after last use.
Heavy daily users: May never drop below 2 ng/mL during active use periods. Metabolite levels may exceed the 50 ng/mL blood or 35 ng/mL urine thresholds for weeks.

The only safe approach under Ohio law: do not drive for at least 24 hours after consuming cannabis, and understand that even this may not be long enough for some individuals.

Alternatives to Driving

Plan your transportation before you consume:

Rideshare services: Uber and Lyft operate in all major Ohio cities
Designated driver: Arrange a sober driver before consuming
Public transit: COTA (Columbus), RTA (Cleveland), Metro (Cincinnati) serve major metro areas
Taxi services: Available in all Ohio cities
Walk or stay put: Consume at home or at a location where you can stay overnight

Cannabis in Your Vehicle

When transporting cannabis in Ohio:

Keep all cannabis in its original sealed, child-resistant packaging
Store cannabis in the trunk or an area not accessible to the driver or passengers
No open containers: Open or partially consumed cannabis products should not be within reach of anyone in the vehicle
No consumption in vehicles: Consuming cannabis as a passenger is a third-degree misdemeanor under SB 56 — up to $500 fine and 60 days in jail