It will be interesting to see if the trend continues to rise ever "higher", pun intended, as use of marijuana becomes more mainstream and as recreational marijuana sales become legal in more jurisdictions.
Personally, I'm not going to be one who will enjoy a drive in Colorado or Washington State until information like this becomes more available.
A Canadian conservative is one who believes in limited government and that the government should stay out of our wallets and out of our bedrooms.
if you disagree simply answer the questions: How many were high during the accident? how many caused the accident? of those how many accidents were caused by being high?
Until those questions are answered the OP and the PDF are worthless and totally debunked based on the premises they were presented.
Let us all know when you can answer those questions.
“Most people do not listen with the intent to understand; they listen with the intent to reply.”
― Stephen R. Covey