People v Koon reversed. Mich SCt Holds that Medical Marijuana patients can drive as long as they aren't actually intoxicated.

Reversing the Michigan Court of Appeals, the Michigan Supreme Court has held that Medical Marijuana patients can drive cars with a detectable presence of THC in their system as long as they are not actually impaired. The Court of Appeals had ruled that Michigan’s zero tolerance policy on “drugged driving” controlled. This meant that the presence of active THC was sufficient to convict the defendant.

The Supreme Court reversed holding that the protections under Section 4 of the Medical Marijuana Act controlled. The Court specifically noted that Section 7 of the Act provided that nothing in the Act would prohibit the prosecution of actually driving while impaired. The Supreme Court suggested that the Legislature adopt a standard analogous to Washington’s which prohibited 5 ng/ml of THC in a person’s system.
People v Koon, Supreme Court No. 145259