In my opinion and experience, many cops (not most, not all, but many) drink and drive and routinely break many other rules of the road. They know that if they get pulled over they'll most likely get "professional courtesy", especially if it's by someone in their police department. One set of laws for the law enforcers, another for the rest of us.
'round here friend, the person you would want to know that you broke the law last is your boss. No kidding.