Based on the total body of knowledge presently available, the commission finds there is no scientifically supported threshold of (THC) bodily content that would be indicative of impaired driving due to the fact that there is a poor correlation between driving impairment and the blood (plasma) levels of (THC) at the time of blood collection, the Impaired Driving Safety Commission wrote in its final report, issued in 2019.
Recreational marijuana is legal in Michigan, and it s already illegal to drive while intoxicated in the state. But marijuana intoxication is not defined in the same way as alcohol intoxication; if someone has a blood-alcohol concentration of .08 or higher, that person is legally considered too drunk to drive.