I am used to being pulled over in the normal fashion. Typically my car is in a lane of travel, and moving (faster than the speed limit), when a LEO vehicle approaches from behind, with blues flashing, at which point I pull over, stop, turn the vehicle off, and wait. An odd stop occurred and I'm confused because the situation was opposite of the normal procedure: I was stopped on the side of the road, with the vehicle in park, while dropping off a passenger. I was stopped for less than 2 minutes, and it was not a lane of travel (although I may have been slightly hindering a bike lane, because of all the snow). While my passenger was exiting the vehicle (dome light on, door open, etc.) I noticed flashing blues in my driver side view mirror. After my passenger closed the door, I noticed flashing blues again, so I focused on the side view mirror. A LEO vehicle was parked behind me, IN THE LANE OF TRAVEL, with blues flashing, and then activated the spot light on my side view mirror, blinding me. So I remained in place, in case I was about to be detained/questioned. The LEO deactivated the spot light. I still waited, then the spot was reactivated, and was focused on my side view/driver seat window, again blinding me. At this point I was confident that this indication was not due to an investigation, but more of a indication that I should move my vehicle. Given that the LEO was blocking the lane of travel, and there were no oncoming cars, I performed a u-turn. Again, I was half-blinded by a spot light, and directly in front of a LEO vehicle. If a u-turn was prohibited, it would be idiotic to perform one at that moment. I was immediately pulled over, for illegal u-turn. I get it, if it's prohibited, you have to enforce the law. What I don't get is, if I was not being cited for a violation until after moving my vehicle, why was the LEO shining a spot and using flashing blues on me prior to the offense. How is that proper procedure?