I would think a more logical approch would be a simple logging system (easy with todays on-boards) once a month the guy has to stop by the DMV to have the logs downloaded.
Breathalizer and a photo should meet any legal requirements.
However this .08% BAL crap is BS in my book, a recent study found people texting to be 10 times more dangerous than someone legally impaired. I personally have more "encounters" with idiots yaking on cell phones than any other threat.