Having a Pennsylvania medical-marijuana card does not by itself make marijuana odor evidence of illegal activity, and odor alone is not enough to justify a DUI investigation. Police can, however, consider odor together with other claimed signs of impairment. In a marijuana DUI case, the police video, the exact sequence of questioning, field-sobriety observations, and how the blood sample was handled can all be important defenses.

Commonwealth v. Wallace, No. 1630 MDA 2025