I'm curious how this would be implemented to only detect alcohol impairment, wouldn't it be technically easier to check for impairment of any kind, including dr

I'm curious how this would be implemented to only detect alcohol impairment, wouldn't it be technically easier to check for impairment of any kind, including drowsiness? And I am really interested how they would sort through false positives of a passenger being drunk but the designated driver is not, someone having open alcohol in the car, using alcohols to sanitize etc.