Yes. In fact, thousands of people face “marijuana DUI” charges in Arizona and other states every single year. The legal standard is “impaired to the slighted degree.” Even though there is no universally recognized medical standard for determining marijuana-based impairment – and many people dispute whether “impaired driving” happens at all for marijuana users – it can be a misdemeanor or even a felony. See FAQs “What are the consequences for violating Arizona’s marijuana laws?” and “Can I get a DUI if I am a Medical Marijuana Patient?”