To answer your question, they make new laws. You have to have your turn signal on 100 feet on small intersections, 300 feet on main arteries. Always something to pick our pockets. Also, you have to stop at a light and make sure your car doesn’t hang over the white line, or you are fined for that.
They also make and use these type of laws so they have an excuse to stop you and check for drugs. If they don’t find any drugs (after they tear apart your vehicle) then they give you a warning for the “great threat to public safety”, I.e., not giving a turn signal on a deserted street. As one poster said, “There are so many laws they can make a criminal out of everyone”. It just depends on how selectively they enforce these “laws”.