Cause and effect? Or is it correlation? The Daily Signal  has more on this:
According to the Washington State Marijuana Impact Report , the incidents of marijuana-impaired driving are increasing dramatically. Fatal driving accidents have risen 122 percent between 2010 and 2014, according to the Washington State Traffic Safety Commission. Marijuana is big business in Washington state. There are more marijuana businesses than Starbucks in Washington state (despite the fact that Starbucks was founded in Seattle).
The traffic safety organization AAA has its own reports  on marijuana use among drivers in fatal crashes, and the picture is equally bleak.
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