Traffic Q&A: 'How are you supposed to know if you're too stoned to drive?'

By Rob Carson, The (Tacoma) News TribuneNovember 12, 2012 

TACOMA -- "Our new law that 'legalizes' marijuana says you're guilty of DUI if you have more than 5 nanograms of THC per milliliter of blood. Is there some way of relating that to how much you've smoked? How are you supposed to know if you're too stoned to drive?"

-- Chester, Tacoma

Answer: There's no way to estimate your active THC blood level by counting tokes or even by how stoned you feel. The potency of different cannabis strains and people's individual reactions vary too much.

One of the only people we know who have been curious enough to get tested is Morocco Kyashna-Tocha, who runs the Green Buddha Patient Network in Seattle.

"I took one good big hit of hash when I got up at 4:30 in the morning," she said. "I got tested at 8:15 and was at 3-plus nanograms."

The best advice: If you've been smoking, do the rest of us a favor and don't get behind the wheel.

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