As a police officer, I can state that in my experience 10 to 15 mph over is generally accepted by most reasonable officers.
#1 EVERYONE speeds. Why do I want to waste my time on the guy doing 67 in a 55 and keeping up with traffic when I can wait a minute and get the guy doing 85 in a 55 and causing a larger hazard?
#2 Liberal judges. Technically 56 mph in a 55 mph zone is speeding. Judges would lose their minds if I "wasted" their time writing tickets for 5 or 7 mph over
#3 Speedometers on most civilian cars aren't 100% accurate. I am a reasonable person, I realize that speedometers can be off a little bit.
I don't understand why everyone on here gets so bent out of shape by what OTHER people do. If one guy wants to drive 55 in the 65... that is his right. I would hope he stays to the right so as to not disrupt traffic though. If someone wants to drive 85 in a 65... that is his choice. If a cop pulls him over and writes him up, then he lost the gamble. If he can avoid a citation and get to his destination safely, then he won the gamble.
Why do some people get so worked up about things that they have no control over...?