A question right up my alley, being a cop and all. First things first. When he approached your vehicle, did he ask "Do you know why I stopped you?" Because that's entrapment. Did you receive a ticket stating you were going 73 in a 35, or did he just say that? The only way to fight it is in court. Any witness that is inside of the vehicle is usully immediatly discounted as they are not partial witnesses, so that won't fly either. There are a couple of ways cops get a speed record from you. A> By aircraft. They measure the distance between 2 areas, time how long it takes you to get there, deduct the speed. I doubt that this is the case in a 35mph street. I'm willing to bet my career on that. B> By radar/laser. These readings are recorded and entered with the officers evidence of your speed. In this case, the speed recording is accurate, but there is human error as far as if he pulled over the correct vehicle, and there are logs he must fill out to calibrate the radar before each shift. If he forgot to do so, the ticket can be thrown out for a faulty radar reading. C> Follow you and match your speed, thus gathering your speed on his calibrated speedometer. This would only hold up in a hard court case if he had a video camera running, capturing your speed for more than 30 seconds while following you. I don't know which method was used, but I'm going to go with statistics and say it was with radar/laser. If it was with laser, your only argument is human error in pulling over the wrong vehicle. If it was Radar, you have that argument plus can have it checked as to whether or not he calibrated his radar that shift. In any event, unless he made a very noticeable mistake, your best bet is to hire an attorney and have him review the evidence and fight it for you. It will be worth the money in the long run. Going to court and saying that the people in the car saw you going 50 will not be effective.