Jacob Sullum on the Elusive Link Between Pot and Car Crashes



Although experiments show that marijuana impairs driving ability, the effects are not nearly as dramatic as those seen with alcohol, and measuring the real-world consequences has proven very difficult, as demonstrated by landmark study released on February 6. In "the first large-scale [crash risk] study in the United States to include drugs other than alcohol," the National Highway Traffic Safety Administration (NHTSA) found that, once the data were adjusted for confounding variables, cannabis consumption was not associated with an increased probability of getting into an accident.

Some news outlets accurately reported that result, writes Jacob Sullum, and some did not, apparently because some reporters actually read the study, while others were content to skim NHTSA's press release. Sullum sasy such carelessness misleads policy makers who are grappling with the issue of how to determine when people are too stoned to drive and aids pot prohibitionists, who cite the prospect of more blood on the highways as an important reason to resist legalization.