How high is too high to drive?

A group of volunteers in Washington smoked "Blueberry Train

Wreck" and were let loose on a closed course (monitored by police

and emergency staff) . A regular smoker of marijuana tested above

the legal limit to begin with, drove without much of a problem. Two

casual smokers also navigated the course without incident. The

method they want to use to measure how high one is. Testing for

nanograms of THC the psychoactive ingredient marijuana per

milliliter of blood. Bob Calkins, a Washington State Patrol

spokesman, had this to say. "We don't just pull people over and

draw blood... If you're driving OK, we're not going pull you over.

But driving impaired is still driving impaired."