Quote Originally Posted by HighPopalorum
Again: If you want to know your blood THC level you should take a blood test. If you're asking me, instead, for a practical rule of thumb that will work for most people most of the time, like the "two drinks" rule I suggest the following: don't drive if you've gotten high that day.
Even if that doesn't constitute impairment? That sounds like a great way to be safe, but why not just set the legal level to 0 nanograms?

Thanks for the tip GM.