Analysis of Impaired Drivers [6]- Three years ago, about 19 percent of the samples contained THC, the key ingredient in pot. This year, that percentage is up to 33 percent.
Links
[1] http://www.npr.org/2015/08/19/432896393/more-washington-drivers-use-and-drive
[2] http://rethinkpot.org/tags/washington
[3] http://rethinkpot.org/tags/driving
[4] http://rethinkpot.org/tags/fatalities
[5] http://rethinkpot.org/tags/car%2A
[6] http://media.npr.org/assets/news/2015/08/THC-1.pdf