He might have just wanted to scare you a little so you'll be more careful next time. But who really knows ?
Because if he'd actually gone up to your window to speak to you, your pretty face would have made his knees all watery and he'd be unable to focus. A good police officer will put himself in the line of danger, but has to realize his limitations too. Since his chums would have laughed their arses off when he called for backup, he thought he'd leave well enough alone. Too bad, though. He might have asked you for your phone number.
I think he got a call for something else, maybe it was from his wife or child and that's why no lights. Maybe he decided he didn't want to do the paper work for a small traffic infraction or maybe he realized he met his quota and was more concerned with getting something to eat.
Haha, its always the donuts huh. Lucky for you though right :)
bigger fish up the rd
Probably just ran your plates through the system.
Something better to do?
Stop trying to guess why, got lucky indicate next time : )