Driving and Drugs: Ohio’s Per Se Marijuana Law

DUI Information
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Charles is a frequent speaker and a prolific writer on all matters related to OVI / DUI defense.

 Wondering if you can get charged with an OVI from Marijuana? 

While it is well established that alcohol consumption increases accident risk, evidence of marijuana’s culpability in on-road driving accidents and injury is far less clear. Although acute cannabis intoxication following inhalation has been shown to mildly impair psychomotor skills, this impairment is seldom severe or long lasting.  According to the US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drugged Driving: FINAL REPORT. op. cit., “Experimental research on the effects of cannabis … indicat[e] that any effects … dissipate quickly after one hour.”  According to the 2004 National Highway Traffic Safety Administration factsheet, Drugs and Human Performance, peak acute effects are typically reached within 10 to 30 minutes after inhalation.

In Ohio, a person is guilty of DUI if he or she operates any vehicle under the influence of alcohol, a drug of abuse, or a combination of them. Ohio Rev. Code Ann. § 4511.19.  In Ohio the threshold for drugged driving is illustrated in the following table. Ohio’s DUI Per Se Levels Id. § 4511.19(A)(1)(vii); Id. § 4511.19(A)(1)(viii)(I)-(II).

Prohibited SubstanceUrineBlood
Marijuana10 ng/ml2 ng/ml
Marijuana metabolite35 ng/ml50 ng/ml
Marijuana metabolite in combination with alcohol or other drugs15 ng/ml5 ng/ml

The above levels establish a per se level above which a person is considered to be statutorily impaired by marijuana. Ohio’s law represents the imposition of per se laws for drivers who test positive for THC in the blood without additional demonstrable evidence of psychomotor impairment.  Just like with alcohol, the “legal limit” is not linked with any qualities of the individual, including weight, frequency of use, time of last use or the bodies ability to metabolize THC.  The penalties imposed for a violation of the marijuana per se law are equivalent to the penalties for OVI.