Well he got tazed because he did not put his hands behind his back when instructed to do so...but my question is,why was he being arrested? Is it a crime to not sign a ticket? because as far as I could tell from the officers words,he was being arrested for refusing to follow his instructions(sign ticket). The officer never did tell him how fast he was going...(I would assume that info would have to be on the citation)The Cop got carried away but the dude should have took the hint when the thing was pointing at him. It doesn't matter..hell he could have shot him in the head and nothing would be done to him. Abuse of authority. Cue KH300 to defend this asshole. 
I'll start off by saying I'm NOT a cop but I did work in Law Enforcement over 15 years ago. One reason I left is due to cops like this who are not trained well and have poor communications skills. I think this police officer needs some training at a minimum as he did not have to use the Taser. The driver was at fault too as he did not follow instruction even-though they were not given with the most tact.
In regard to the guy not signing the ticket, he is required to sign the ticket to be released from the traffic stop. In the eye of the law you are in police custody during the traffic stop. To be released from that custody you must sign the ticket saying you understand the ticket and that you understand what you need to do to remedy the ticket (go to court or pay for it). Now the officer did not explain either of the two points and the guy had every right to ask for an explanation. However, the drive was told that he was pulled over for speeding. If he had taken the time to look at the ticket it would have provided the detail that he requested. That would have avoided the officer asking him to get out of the car.
In regards to what happened after the guy exited the car, he did not follow instructions. He has no right to refuse the officers orders in order to see the signs that may or may not been on the road. He can go check those things out after signing the ticket and obtain evidence to support his case afterwards. The officer has an obligation to ensure the safety of the guy too. If you watch the video when the guy was questioning the locations of the sign he was stepping very close to the solid white line. If a car had come by too close it could have hit and injured him. So he must follow the officers instructions and have his day in court later.
Now the use of the Taser was completely inappropriate in my view. By pulling it out the officer escalated the situation and made the driver go into a flight mode. I don't think the guy was going to run but he was freaked out and started backing close to the lane of traffic. The officer could have achieved the same thing by just grabbing the guy by the arm and directing him to the car. If the guy resisted then he could use additional force.
So in the end these two guys got into a pissing match over something that trivial. Unless the guy is a psychopath, the cop is always going to win on the side of the road. Later, the courts can figure it there was malfeasance.
