Abstract
The effects of cannabis and alcohol on simulated car driving were studied at the Psychochemistry Institute in Copenhagen. Cannabis resin containing 4 percent tetrahydrocannabinol was administered orally in 3doses equivalent to 8, 12, and 16 milligrams of that component. Alcohol was given orally in one standard dose of 70 grams. Both cannabis and alcohol increased the time required to brake and start, whereas alcohol increased while cannabis decreased the number of gear changes.