The number of drivers involved in fatal collisions in Colorado who tested positive for marijuana has risen 145 % between 2013 and 2015 , according to federal and state data . Colorado legalised the drug in late 2012 . The evidence does not indicate whether a fever was high at the time of the crash , however , as traces of marijuana can remain in the car for weeks , therefore it is impossible to confirm definitively that the drug 's legalisation is behind the rising death count .
The number of drivers involved in fatal collisions in Colorado who tested positive for marijuana has risen 145% between 2013 and 2016, according to federal and state data. Colorado legalised the drug in late 2012. The data does not indicate whether a driver was high at the time of the crash, however, as traces of marijuana can remain in the blood for weeks, therefore it is impossible to state definitively that the drug's legalisation is behind the rising death count.