There’s a multimillion idea. I’ve thought about it.
But theoretically, you can smoke Friday night, chill at home over the weekend, drive to work Monday morning, sober as can be - and if you’re pee tested, certainly hair tested, you’ll be positive. So it’s different than ETOH.
Though, there are chronic alcoholics with a sliver of a liver left walking around fully functional, not drunk, with high BACs.
If you could develop an accurate field test for THC that differentiates stoned from mere presence, you’re rich.
