Cont'd. Driving while high: "in a study of 1,882 motor vehicle deaths, the US Department of Transportation found an increased accident risk of 0.7fro cannabis use, 7.4 for alcohol use, and 8.4 for combined use. The simultaneous use of alcohol and cannabis produces significantly higher blood concentrations of Delta9-THC, as well as THC primary active metabolite, 11-hydroxy-THC, than cannabis use alone (from "any dose of alcohol combined with cannabis significantly increases levels of THC in blood" 2015. Journal of Clinical Chemistry). The take-away here: COMBINING cannabis & alcohol is a major problem, not necessarily cannabis alone.