The police wait until they have an isolated vehicle then they deploy their radar/laser, then they light you up and ticket you. End of story.
They're starting to use them in The People's Republic of Massachusetts, except with a twist...
It's common for everyone to go about 75 (in a 65), which means to pass someone safely, you need to be going 80 ish. (Since we have our share of left lane hogs, and tree huggers with Prius' and attitudes who never get ticketed, sometimes it can be a real pain to get over to the right lane to exit...but I digress...)
However, this is what (some cops) do now to meet their quotas...eh, I mean "performance goals". When they see someone going slightly more than keeping up with traffic, they pull you over and claim you're going "just over 90" and they clocked you on laser. They tell you that because going that fast is felony speeding, and they could arrest you and impound your car, which of course they explain to you in detail...BUT, since they're your buddy, your pal, your bum chum, they'll reduce it to 80 and "let you go" (whenever they stumble upon a new technique to raise supplemental road tax, like tailgating, they tell each other).
This has happened to several people I know. They do this so you're afraid to fight the ticket.
I basically have a surveillance package. I use a Cobra Atom radar detector, connected to the internet with iRadar, and Waze, and also a dashboard video camera with a camera facing out the back of the truck, and a camera facing the drivers door. I trust nobody. Even though I haven't been pulled over since the 20th century, I had too many bad experiences with oath breakers in my youth. Man, I went on a 4 hour round trip on Memorial Day weekend with my girlfriend, and Waze alerted us to every single one of the 27 speed traps we drove through.