Studies in Colorado and Washington State, the first two states to legalize marijuana for recreational use have found huge increases in motor vehicle deaths since pot was approved.
In Colorado, marijuana-related traffic deaths rose 66 percent in the four years since legalization (2013-2016) while, during the same period, all traffic deaths dropped by 16 percent.
In Washington State, the number of marijuana-related traffic deaths doubled during the same period.
In both states, there was an alarming increase in the number of arrests for impaired driving that can be traced to marijuana use. In Washington, the proportion of suspected impaired driving cases that tested positive for THC rose from 19 percent in 2012 before legalization to 25 percent in 2013 to 28 percent in 2014 and 33 percent in 2015.