Already, not everyone is happy with this. The group Patients Against New Approach Washington says this level is not supported by science and would subject suspected impaired drivers to highly-invasive blood testing, unnecessary confinement and a criminal conviction that will haunt them for life.
They consider the zero tolerance clause for those under 21 even worse though, because a designated driver subjected to second hand marijuana smoke could be held criminally liable for the acitivities of others.
Because I can't find a website for the Patients Against New Approach Washington group stating their concerns, I'm going to link to a site I never thought I would use, Toke of the Town. I believe the article posted there on this topic has factual information and some valid points, but be warned that if you go to this site there is some PG-13 content, to say the least.