The unmarked car didn't pull him over, it blocks him at a light at an exit from the interstate.
Again, it sure seems there is more to this story than a speeding stop.
Did the marked car try to have the guy pull over on the interstate and the guy didn't? How did the unmarked car become involved? Unmarked cars are often used for speed control, was that the case?
A 'routine' traffic stop, to me, must be one of the most stressful events in an Officers life. you never know what the offender might be thinking or about to do.
I was pulled over for speeding one evening and the officer told me my speed was measured by LASER and I asked to see the equipment. He said ok and asked me to come back to the cruiser. I got out of my car and as I turned to head back, I saw the second officer off on the shoulder, gun drawn and in a position where he was watching the back of my head while the first officer approached the drivers window.
Have no idea if that is accepted procedure, but I do understand the risk taken by officers.
I always have my wallet out and in my hand, with both hands on the wheel and the window down when the officer approaches. I don't want them to ever have to wonder what my hand is doing out of sight.