Marijuana metabolites remain in your blood for days after use. In these circumstances, the police can charge you with DUI because of the existence of metabolites in your blood. This causes what we will call a “metabolite DUI.” In Pennsylvania, it is illegal to “drive, operate or be in actual physical control of the movement of a vehicle” when “[t]here is in the individual’s blood any amount of a Schedule I controlled substance . . . or metabolite of a substance[.]” 75 Pa. C.S. § 3802(d). That means that the mere presence of a metabolite in your blood is enough to convict you of DUI.