Worries about legalized marijuana led state lawmakers to create the Michigan Impaired Driving Safety Commission, which is due to submit a report and recommendations to the Legislature and governor in March.
Now that marijuana is legal in Michigan, it should not be illegal simply to have marijuana in your system while you are driving. It should be illegal to drive while you are impaired, just like it is with alcohol and prescription narcotics. People can responsibly drink alcohol without driving while drunk. Similarly, they can recreationally use marijuana without ever driving while they’re impaired.
Some states that have legalized marijuana are using per se laws, as they have for alcohol. With per se laws, you basically have the standard .08 blood alcohol content limit and the law treats anyone with blood alcohol content above that level as a drunk driver. But applying this approach to marijuana is problematic.