I've watched the video three times. Here's essentially what happened. Trooper Gardner pulled Massey for speeding. He walks up to Massey's SUV and says, "How are you doing? You were going kind of fast. Need your license and registration." This is one of the few times that the two men clearly understand each other and each other's intentions during the 10 minutes captured by the dashboard camera. Another moment of clear communication comes when Massey—who stupidly wants to argue his guilt or innocence with the trooper on the side of the road—refuses to sign and accept the citation.
The trooper then orders Massey out of the vehicle. Massey is clearly not aware at this point that he is under arrest. He keeps arguing his case as Trooper Gardner orders him to "turn around and put your hands behind your back." Gardner pulls his TASER and continues to order Massey to turn around and put his hands behind his back. Massey is too clueless to realize that he is about to get zapped, so he turns his back on Gardner and starts to amble back to his vehicle. So, zap.
How you view this footage is clearly determined by your experience with traffic stops. If you are a cop or someone who has seen a lot of dashboard videos in which officers get killed, you can understand why Trooper Gardner decided to TASER motorist Massey as he moved toward his car. But to the public, this looks like a case of an officer of the law TASERing a guy just because he was arguing with him.
Don't believe me, take a quick scan of the following quotes from the comments that were submitted by readers of the Salt Lake Tribune at the bottom of the story announcing Massey's $40K award:
First, from the "all cops suck" crowd.