This is very simple.
Routine traffic stops catch wanted criminals. That's why they make them. If they didn't work, they wouldn't do it. If you don't believe it, ask the police or watch 'COPS' sometime.
edit: Of course, they also make stops because you broke a traffic law. There is a period of time where detectives might be looking for someone - if they know who they are after, traffic stops are just one more way those people are caught.
I have been stopped several times by the police and never once have they asked to search my car or my person. I have nothing to hide, but if they asked I would tell them to get a warrant.
Guess what - you won't be stopped by the police if your obey the law. Whenever I have been stopped, it is because I was not obeying the law.
I suppose in your world patrolman, whose duty it is to enforce traffic laws, should ignore speed, dangerous/reckless driving, people running lights, etc.
edit again: I'm going to take a wild guess and say you've been stopped by the police and they found contraband on your person or in your car.