After a traffic accident the police and troopers run blood tests. The Washington Traffic Safety Commission says a positive result for marijuana does not necessarily mean they were high while driving. But new testing procedures reveal "most" were last year.

In 2010, 64 percent of drivers positive for pot had active THC in their system. In 2014 it was 85 percent! But the THC level only exceeded the legal limit in half the cases. But half of the THC-positive cases were also over the limit for alcohol.

In 2013 only six tested drivers age 21-25 were active THC positive. In 2014 it was19.

Understanding that only a portion of drivers involved in fatal accidents were tested, and only a portion of those tested positive for drugs, and only a portion of those tested positive for marijuana, and only a portion of those were positive for THC, it is difficult to measure the seriousness of this finding.

What the commission is sure of, however, is that THC is now playing a part in some of the worst traffic accidents in the state.