How exactly would an automated sobriety test make use of a qualitative metric?
Is a score on a video game quantifiable enough for you? There are so many "brain training" games that do nothing but score you on your observation, working memory, reflexes, etc. Back in college, everyone had to participate in the psych experiment test pool, where many of the experiments were coded in extremely rudimentary Visual Basic, to show video clips and record the time intervals between on-screen events and keypresses.
That's more objective than a human checking your eyeballs to see if there are too many involuntary movements, or making a subjective determination that there weren't enough social displays of submission to the tester. And it scales better to have X computers set up for employees to test and clock in at the same time than to have a supervisor processing the whole line one by one.
Exactly. The only downside I imagine is that it could give false-positives to retarded people. Reaction speed is pretty well correlated with intelligence.
I suppose the system could compare your current score with your baseline / sober scores. Or, mentally slow people would simply have less tolerance for being fucked up at work.
That could be fought while there is little leeway in terms of fighting "my training and 15 years of experience allowed me to determine that the subject was impaired".