FRANKFORT, Ky. (FOX 56) — The question of how to measure marijuana intoxication behind the wheel often puts law enforcement in a difficult position.

Currently, Kentucky law calls for a blood test if a police officer suspects a driver is under the influence of marijuana. But, marijuana can be detected in a person’s system long after use, so the results don’t always reliably prove whether a driver was high behind the wheel.

Sen. Johnnie Turner (R-Harlan) is proposing a bill that would update the law to utilize technology that can measure THC on a micro level and set a limit for intoxication, much like current alcohol DUI laws.

“There’s no testing now, except they take your blood test,” said Sen. Turner. “The whole world knows that you can be riding in a car, and somebody is smoking marijuana, and you are just inhaling it through theirs. It’ll show up in your system, and it can stay in there for 30 days. So this bill is trying to get something that’s fair both to the public, who may have been around somebody smoking, or somebody that smoked it a month ago.”


Senate Bill 228 would set the limit to 5 nanograms. States that have passed similar laws have set their limits between 2-5 nanograms. The limit was recommended based on the advice of physicians.

The bill passed the committee unanimously without much input from law enforcement.