To give you some idea of how "well" we are served by our boys in blue, I offer not one, but three true stories:

1) My wife was literally run off the road in Fort Wayne (Indiana 2nd largest city). It was snowing. She called me and said the guy took off, but she got his license plate number. I call the cops and, unfortunately for us, one of the dumbass hillbillies we call police officers managed to shoot himself in the leg. The dispatch operator says, "We can't go down there to help her now. We've got an emergency. One of our policmen was shot and all available units are responding."
I hurry to her with a tow rope and pull her car back on to the road and she makes it home. Thanks for the help, pigs.

2) I am involved in an accident where my car flips over. I crawl out, call the cops, in 6 degree weather with snow, and 70 minutes later a cop finally shows up.

3) Finally, when did the cops go into the building where the Virginia Tech gunfire was going on? Answer: After the shooting has stopped and everyone was dead.

Yeah. Good advice. "The cops will save me." Might work across the pond, but here you are vastly more likely to be screwed by a cop than you are to ever be helped by one.