Every police department, from state to state, has their own take on this matter. Usually, police officers are urged by their superiors to obey laws like ordinary citizens, however, there are many reasons why you may see an officer breaking a traffic law/regulation without the use of their lights/sirens.....
For example, when an officer gets a call of a home burglary in progress, this means that the perpetrator is in the act of burglarizing a home, which means that the perp is still there (hence, "in progress")......Picture it being YOUR home...... Would you rather the officer hurry up and get there (run stop signs, break the speed limit) to stop and catch the perp, or would you rather have the officer use their lights/sirens and scare the perp away, who can hear the sirens from miles away, or would you rather the officer just obey all traffic laws (stopping for red lights, obeying speed limits) and take their time getting there? How do you know for absolute certainty that the officer is just driving or responding to a call?
There are many reasons why you may see an officer driving "routinely" and break a few traffic laws. Yes, police officers should lead by example, however, in the future, when you see an officer breaking a traffic law, take a moment to think if you know for sure wether they are responding to a call or not. Who knows? You DON'T know for sure, so why not give an officer some slack?
7 years Law Enforcement experience....and counting.