Subaru Wagons. Any Volvo.
Drivers of these rolling roadblocks are the self-appointed guardians of the speed limit, often bringing it down a few notches for good measure. Safety and civic responsibility are obvious personality traits of these motorists, but they should endeavor to keep their attitudes out of the passing lane. I would wager that even cops sometimes want to run them off the road. Speaking of cops:

Police Cars: Situation One.
When a police car rolls up behind you, please get out of his way. He is very likely on a call, or on his way to see something more interesting than your back-end. If you are one of those people who stay in front of police cars, slowing to the speed limit because you are paralyzed with fear, or want to show what a model citizen you are, or are driving a Volvo and behaving normally, you need cut it out. The officer knows how fast you were really going because he saw you three miles back. If I were a cop, and the law allowed it, I would bust you for insulting my intelligence. Just pull out of his lane, let him pass, then resume speeding.

Police Cars: Situation Two.
If you roll up on a police car it is OK to pass -- if you use proper protocol: Slow to match his speed, then gradually accelerate away. You have acknowledged his presence and authority and are very conscientiously not impeding traffic behind you. If, however, you zip right past because you did not see him, or simply don't care, he must, and will stop you.

The moment a car blows past a police cruiser, that officer is in the spotlight. Every other driver on the road immediately glances at him to watch what he does. To prevent your making a chump of him, and to save face with the other drivers -- and satisfy their desire to see you get nailed (which further reinforces his authority), the officer must, and will, pull you over. It is now up to you to be on your best behavior, perhaps feign ignorance and, if you play it right, get off with a warning.

Cell Phone Zombies
What can I write about these people that you do not already know?

Passive Aggressive Drivers
My favorites. Because they impede the flow of traffic, these folks are:

The source of all road rage.

It is a safe assumption that every reader of this article, cruising along at a cheerful 70 mph pace, has come upon that one driver who insists on maintaining 55 mph in the passing lane.

Fully aware of the empty pavement ahead of him, the traffic jam behind him, and the other motorists zipping past him on the right, Mr. Passive Aggressive refuses to vacate the left lane because he rationalizes he is obeying the letter of the law, even though it is at the expense of common sense, safety and courtesy.

What he is really doing is being a selfish jerk, for whom Rodney King protocols should apply, if he ever commits a traffic infraction.