You were around weed smoke in a car with the sun roof cracked open for about 20 mins on two separate days Can fail an drug test the day after?

I don't think so. If you would have asked this 25 years ago when they were just starting to run drug tests I would have said yes. They had the cutoff levels cranked down real low to catch all the dopers they could, and people who hadn't ever smoked were coming back red hot from being at concerts and stuff. Now they've turned the levels up pretty high, so you really need to smoke in order to be hot.
I don't think so. If you would have asked this 25 years ago when they were just starting to run drug tests I would have said yes. They had the cutoff levels cranked down real low to catch all the dopers they could, and people who hadn't ever smoked were coming back red hot from being at concerts and stuff. Now they've turned the levels up pretty high, so you really need to smoke in order to be hot.