Well, here is the deal... If you are good at debating and can handle yourself, you can go to court and tell the judge that the "posted" speed was wrong. When he says... "It's just a simple mistake and so we'll just go with the difference." Tell him that there being an error on the ticket shows that there are mistakes and the speed he actually clocked you might be ANOTHER mistake. I've run into this problem as well. If you don't stand up for yourself, they will just change the posted speed and carry on with issuing you a fine. (Been there done that) Now that I know what I know... It will never happen again, TRUST me. Good luck and let us know what happens.