In Michigan, the answer is yes and no. In 2013, Michigan’s Supreme Court ruled unanimously that Michigan Medical Marijuana Act trumped the zero tolerance laws. That said, if you are a Medical Marijuana patient, the presence of THC in your system can’t be used solely to convict you of DUI. However, other circumstances such as failing to control your vehicle, weaving, etc can lead to DUI charges. Being too high to drive can probably be determined by police simply giving you the same tests that they do to determine when drivers are suspected of being drunk.
In Michigan, a person is deemed guilty of DUI if they operate a motor vehicle under the influence of marijuana. If an officer suspects a driver to be on marijuana they can request a blood draw test to determine if any amount of marijuana is present over the legal limit.
Yes, you can get a DUI for smoking weed in Michigan. However, The Michigan Supreme Court decided that inert metabolites of marijuana as a controlled substance. This means that qualified patients who may use Marijuana may be able to drive after using the substance with now consequence as long as under a certain level. These levels can be determined by a chemical test at the time of being pulled over.