My father-in-law recently went on a police "ride-a-long" (we live in Virginia Beach, VA). He said that in between responding to domestic disturbance calls, the majority of the time was spent driving around scanning license plates. Prior to that, he didn't even know the police had the capability, much less the desire to track innocent folks. One particular incident occured that night when they pulled up to a vehicle that came up stolen. The cop pulled the guy over, handcuffed him and put him in the back seat. The guy was upset, and for good reason, which would only become clear some minutes later. He was the owner of the car which had previously been reported as stolen, but had not been cleared in the database after it was returned to him.
The problem here isn't the police pulling over the reported stolen car, it's their assumption of guilt. Handcuffing someone before you even talk to them? This just doesn't seem to happen in the UK. When I was young I was pulled over several times, once on the motorway, I'd been doing 87 (speed limit was 70), and I was talking on a mobile.
They pulled me over, walked up to the car, asked me to get out of the vehicle on the passenger side and come back to to their car, where they gave me a ticket (not a speeding one, but one for the mobile)
Another time I was pulled over with a bald tire. They let me park the car first, then again asked me politely to join them while they wrote me a ticket.
There's something in the american psyche that causes the police to be adversarial.