To nab drunk drivers, authorities can administer breath tests to confirm whether someone is over the legal limit.
But how do officers decide whether a driver is high, especially now that adult-use recreational marijuana is legal statewide?
Unlike with alcohol, there are no instant tests to determine a person’s level of THC, the main psychoactive component of marijuana-derived products.
Many factors, such as forms of administration, dose, body composition and tolerance, can affect how long marijuana consumers need to wait before they are no longer what law enforcement determine as appreciably impaired and OK to drive, said Christopher Kinn, an Ohio State Highway Patrol captain and executive officer in its Office of Field Operations.
The body processes THC differently when it’s ingested than when it’s smoked or vaporized; ingested THC has a longer onset time.
In any case, Kinn said, “it would be several hours before those abilities are no longer appreciably impaired.”
The Highway Patrol recently joined a pilot program using saliva to test for THC on a limited scale, Kinn said, but the agency does not currently use the results to make arrests.
Urine testing is the typical toxicology protocol in operating a vehicle under the influence (OVI) cases, as many law enforcement officials can’t draw blood, Kinn said.
But because THC can be detected in a person’s urine well past the point of actual intoxication, particularly in regular marijuana consumers, Kinn said urine tests alone aren’t used to make an arrest.
Instead, he said, results are combined with other techniques to meet the legal burden of proving someone is intoxicated “beyond a reasonable doubt.”
Law enforcement officers determine impairment in drivers by checking whether their eyes make involuntary, repetitive and rhythmic movements from side to side and by administering walk-and-turn and one-leg stand tests, according to Kinn and Summit County Sheriff’s Office deputy Dan Cuckler.
There are no laws on Ohio’s books by which law enforcement can arrest someone for driving under the influence of synthesized THC “isomers” such as Delta 8 and Delta 10, Kinn said.
Aside from driving high, driving marijuana over state lines and smoking or vaping marijuana as a passenger are illegal.
Patrick Williams covers growth and development for the Akron Beacon Journal. He can be reached by email at pwilliams@gannett.com or on X, formerly known as Twitter, @pwilliamsOH.
This article originally appeared on Akron Beacon Journal: How Ohio police determine if someone is too high on marijuana to drive