Please use this link to access this publication. Abstract Background: Cannabis legalization is expanding, but there are no established methods for detecting cannabis impairment. Aim: Characterize the acute impairing effects of oral and vaporized cannabis using various performance tests. Methods: Participants (N = 20, 10 men/10 women) who were infrequent cannabis users ingested cannabis brownies (0, 10, and 25 mg Δ-9-tetrahydrocannabinol, THC) and inhaled vaporized cannabis (0, 5, and 20 mg THC) in six double-blind outpatient sessions. Cognitive/psychomotor impairment was assessed with a battery of computerized tasks sensitive to cannabis effects, a novel test (the DRiving Under the Influence of Drugs, DRUID®), and field sobriety tests. Blood THC...