The saying I recall, is "halfway to 80". That is you don't exceed the halfway point between the posted limit and 80.
Of course, the best advice I ever got was from a web site called something like "never get another speeding ticket". It was written by an ex state cop.
He said most people talk the cop into giving them a ticket before they even get to the window, without realizing it.
Pulling someone over isn't the safest thing a cop can do, They don't know if you're a criminal that's going to pull a gun, or if they're going to have their ass hanging out in traffic and get clipped.
So the whole point is to make them feel more "comfortable" .
- If you can pull off the road completely, do so. Put on your turn signal so the cop knows what you're doing.
- Keep your hands in plain sight and don't reach for anything, or do anything (license, registration, etc.) until he gets to the window and asks you for it. He doesn't know what you're reaching for. It could be a gun.
- When he gets to the window, turn the stereo off, if it's on. If you have volume controls on the steering wheel, and you can turn the volume all the way down, while leaving your hands in plain sight, then do this before he gets to the window.
- If you're wearing sunglasses, take them off. Let him see your eyes.
- When he asks for something, and you reach for it, explain where you're going and what you're going to retrieve. e.g., "my registration is in the glove compartment".