Why Do Cop Cars Have Slogans On Them?

Have you ever thought about that? I was stuck in traffic next a cop car when the “why do cop cars have slogans?” question came to me.

Do they have to say “Service with integrity” to remind the people of the community of what their brand stands for, is it to remind the cops about what they are supposed to provide?

Did you happen to catch in the Transformers movie the slogan written on Barricade when he was a police car?

To punish and enslave
To punish and enslave

It says “to punish and enslave…” which I imagine, would be the appropriate slogan for the Decepticons.

On a different note, I heard a rumor that they chose GM products for the Autobots (the good guys) because GM either gave them money or permission or both to use their cars and they used Fords for the Decepticons (the bad guys) because Ford didn’t or wouldn’t.