This is a feature, not a bug. In fact, many jurisdictions have requirements that, above a breathalyzer-reported BAC threshold, different minimum mandatory puni

This is a feature, not a bug. In fact, many jurisdictions have requirements that, above a breathalyzer-reported BAC threshold, different minimum mandatory punishments are levied. Sure, a sober person won't get a result that's above the legal limit most of the time, but someone who's done some drinking and is within appropriate parameters is often labeled as DUI, and could potentially register as above this higher, mandatory-jailtime, mandatory-felony situation. I've known of cases where the breathalyzer in question has been shown to be broken and decommissioned, yet the people whose numbers were so wildly inflated that they couldn't possibly be accurate have still been convicted using these numbers. In one case in particular, the judge ruled that the evidence on the unreliability of the machines in general (and this machine in particular) was not admissible for court. It's about punishment, not deterrence.