It's not training: they 100% know that you're supposed to signal, stop at red lights or stop signs, park in the middle of a traffic lane, not cross a solid double yellow to pass someone going the speed limit, etc. The people who do that are choosing to do it because they feel whatever they're doing is more important and they know that most police departments stopped doing traffic enforcement years ago because it's beneath post-9/11 warrior cops unless they're looking for an excuse to search someone's car.