There's nothing wrong with having a prescription for marijuana, even if the "prescription" is really just a state medical license provided by a sketchy doctor that you slip 200 USD once a year.
But please stay off the roads while you're under "psychoactive" effects (read: high) . There are LEGAL drugs that are illegal to use while operating a motor vehicle.
Hundreds of millions of adult Americans use psychoactive substances on a daily basis (SSRI, MAOI, SNRI, Caffeine, Nicotine or worse, opiates / benzodiazepines) and are under no driving restrictions or legal ramifications for doing so.
But please stay off the roads while you're under "psychoactive" effects (read: high) . There are LEGAL drugs that are illegal to use while operating a motor vehicle.