I'm all about anti drinking+driving. My father once told me he was 'this' close to pulling his CCW and shooting someone for cutting him off, but he didn't because he had an open beer in the cup holder. But treating every person like they're a drunk driver? What if the tech fails and an innocent person crashes because the technology wouldn't let them drive after a false-positive test for drunkenness? Why not use the money meant for this for drinking and drug use reduction classes, or reformatting the school system to teach moderation, control, knowing your limits, instilling an actual moral compass that says 'commiting crimes like drinking while driving is risky and dangerous?' There are plenty of ways to go about reducing the harm excessive drinkers cause, without infringing on every single citizen's privacy.