Gitem:

I think there are some departments that do a better job with DUI investigations than others. I think there are counties where the jury pool is heavily represented by functioning alcoholics.

Where I've practiced, the win rate for the prosecution in DUI cases is a lot higher than what Joe Bob is describing. Notice he hasn't - so far - given us the stats on his dipso clients who take one look at their DVD and sink into his office floor in embarrassment.