This sounds like surfs in the dark ages. Sherriff says you owe me, and you pay whereby he goes to the next and does the same. Over and over again.
If enough people said, NO, and took the time and effort to show up in court they would do this far less than they do.
You need to fight injustice where ever you can...it is YOUR responsibility as a citizen to make a stand and stop abuse, whether it is bullying a kid on the play ground, or stretch of the laws.
What he is counting on is that you were guilty and you will pay just to have to not fight it.
Stand up an announce that you are a citizen of the United States of America, and like soldiers who fight for our freedom, you will stand your ground when the law is wrong and you are right. You owe it to everyone to do this....paying the ticket might be an economical way to deal with it, but it is akin to robbing a smaller kid on the play ground because YOU CAN....
Now send that ticke in, and get an appearence in front of the judge....if enough people do that...the cop will quit assuming you weren't and only go after those that are extremely obvious....not likely to be wizzing by at 85 mile per hour.