http://www.whitehousedrugpolicy.gov/publications/factsht/marijuana/
Drugged Driving
While alcohol is the predominant substance found in fatal automobile crashes, marijuana is the second most frequently found substance in drivers. Alcohol and marijuana are also frequently found together, resulting in a dramatic decrease in driving performance and spike in impairment levels.
According to a National Highway Traffic Safety Administration Study, a moderate dose of marijuana can impair driving performance. The study also found the effects of a low dose of marijuana combined with alcohol were markedly greater than for either drug alone. Driving performance was measured by reaction time, visual search frequency, and the ability to perceive and/or respond to changes in the velocity of other vehicles.
According to estimates derived from the U.S. Census Bureau and Monitoring the Future data, approximately 600,000 of the nearly 4 million U.S. high school seniors drive under the influence of marijuana. Approximately 38,000 seniors reported that they had crashed while driving under the influence of marijuana in 2001.
yeah sure but, how my article is irresponsible? did you really read the article?? and also what do you think? does marijuana imparis more or less than alcool?