Last verified: March 2026
The 2 ng/mL Per Se Standard
Under ORC §4511.19, Ohio operates a per se marijuana OVI standard. This means the state does not need to prove you were impaired — only that your blood THC concentration exceeded the legal threshold at the time of driving. The threshold is:
| Test Type | Threshold | What It Measures |
|---|---|---|
| Blood THC (delta-9) | 2 ng/mL | Active THC — the primary psychoactive compound |
| Blood THC metabolite (11-OH-THC + THC-COOH) | 50 ng/mL | Metabolites — no proof of impairment required |
| Urine THC metabolite | 35 ng/mL | Metabolites — no proof of impairment required |
The 2 ng/mL blood THC threshold is the lowest per se limit in any legal state. For comparison:
- Colorado: 5 ng/mL (permissible inference, not per se)
- Washington: 5 ng/mL (per se)
- Nevada: 2 ng/mL blood, 10 ng/mL urine
- Montana: 5 ng/mL
At 2 ng/mL, a single cannabis use can keep a person above the legal driving limit for 24 or more hours, depending on the individual's metabolism, body composition, and consumption method. Regular users may exceed 2 ng/mL for days after their last use.
With alcohol, you can roughly estimate when you will be below 0.08% BAC. THC does not work this way. Blood THC levels vary wildly based on tolerance, body fat, hydration, and method of consumption. There is no reliable "hours since last use" formula to guarantee you are below 2 ng/mL. If you consume cannabis, do not drive for at least 24 hours.
Four Types of Marijuana OVI
Ohio recognizes four distinct pathways to a marijuana OVI conviction under ORC §4511.19:
| Type | Standard | Proof Required |
|---|---|---|
| Per se (blood THC) | ≥ 2 ng/mL delta-9 THC in blood | Blood test only — no impairment proof needed |
| Per se (blood metabolite) | ≥ 50 ng/mL THC metabolites in blood | Blood test only — no impairment proof needed |
| Per se (urine metabolite) | ≥ 35 ng/mL THC metabolites in urine | Urine test only — no impairment proof needed |
| Impairment-based | Observable impairment from marijuana | Officer testimony, field sobriety, Drug Recognition Expert evaluation |
The metabolite thresholds are particularly concerning. THC metabolites can remain detectable in blood and urine for days or weeks after last use, especially in regular consumers. This means a daily cannabis user could technically be above the per se limit at all times, even when completely sober.
First Offense Penalties
A first marijuana OVI conviction in Ohio carries mandatory minimum penalties under ORC §4511.19:
| Fine | $375 – $1,075 |
|---|---|
| Jail | 3 days minimum (may substitute driver intervention program) |
| License Suspension | 1 – 3 years |
| Vehicle | Yellow "party plates" required during suspension period |
| Insurance | SR-22 high-risk insurance required for reinstatement |
| Criminal Record | 1st-degree misdemeanor — stays on record permanently |
Repeat offenses carry exponentially harsher penalties, including mandatory jail time (10+ days for second offense), longer suspensions, potential felony charges (4th offense within 10 years), and vehicle forfeiture.
Medical Card Is NOT a Defense
Holding a valid Ohio medical cannabis card provides absolutely no defense to a marijuana OVI charge. The law makes no distinction between recreational and medical consumers for driving purposes. If your blood exceeds 2 ng/mL or your metabolites exceed the thresholds, you are guilty regardless of your patient status or prescription.
SB 55: The Pending Fix
Senate Bill 55 would raise Ohio's per se blood THC limit from 2 ng/mL to 5 ng/mL, aligning it with Colorado and Washington. The bill's status:
- Passed the Ohio Senate unanimously — rare bipartisan agreement that the 2 ng/mL standard is unreasonably low
- Stuck in the House — the bill has not received a committee hearing or floor vote in the Ohio House as of March 2026
- SB 55 would also eliminate the urine metabolite test pathway for OVI prosecution
- Law enforcement groups have not formally opposed the bill, but House leadership has not prioritized it
Until SB 55 passes, the 2 ng/mL standard remains in effect. Every cannabis consumer who drives in Ohio should be aware of this uniquely strict threshold.
The safest approach in Ohio: do not drive for at least 24 hours after consuming cannabis, regardless of how sober you feel. Use rideshare services (Uber, Lyft), designate a sober driver, or stay where you consume. The 2 ng/mL threshold is so low that even experienced consumers cannot reliably estimate when they are below it.
Refusal to Test
Ohio has an implied consent law. By driving on Ohio roads, you have implicitly consented to chemical testing when an officer has reasonable grounds to believe you are impaired. Refusing a blood or urine test triggers:
- Automatic 1-year license suspension (Administrative License Suspension)
- The suspension begins immediately at the time of refusal
- The refusal can be used as evidence against you at trial
- Even without a test result, you can still be convicted of impairment-based OVI through officer testimony and field sobriety evidence
Official Sources
- ORC §4511.19 — Operating Vehicle Under the Influence
- SB 55 — OVI THC Threshold Reform (pending)
- Division of Cannabis Control
For in-depth cannabis education, dosing guides, safety information, and research summaries, visit our partner site TryCannabis.org