Science can be awesome and envious. I now refer you to the November 2010 edition of Accident Analysis and Prevention. Researchers in Israel gave a dozen 24-29 years olds booze and drugs, then tested their performance on driving and non-driving tests. These lucky kids either received a combination of alcohol (or not) and/or 13mg of THC (or not). THC, a.k.a. tetrahydrocannabinol, is the one of the psychoactive substances in cannabis. After ingestion of wonderful botanicals, the results were not surprising. The combination of alcohol and THC had a tremendous negative impact on driving skills. Fortunately these driving tests were only in simulators. Oddly enough these subjects also sucked at other non-driving tasks that assigned to them. The researchers noted no conflicts of interest; other than the fact that the study was sponsored by Doritos.