A: Revenue!
Up here in the hills of CA, DUI checkpoints during the week-ends are up all over the place. Late at nite, get pulled over for anything you're liable to get tested. And, if you test at any BAC level, you're a "drunk driver".
That two glasses of wine over a nice dinner can cost $7500 (or more) in fines, court costs, license points, classes, and insurance costs if you get checkpoint-nailed.
It's a county cash cow; supports a whole DUI-related cottage industry.
So I personally don't roam out late anymore as a DUI hit would impact too many other credentials I hold; limits the social life. The paranoia just takes the fun out of it.
Interesting article and confirms, again, many suspicions.
Thanks for the post.
~GCR~
If the DA is filing on cases less than .08 and there is no showing that the driving was impaired then the DA is being unethical.