In the United States, there is a legal presumption of innocence before being found guilty of a crime, and for noncriminal offenses, the government usually has to show some proof (preponderance of the evidence or other legal standard). It is not your burden to show innocence, but rather the government's burden to show you violated a law. Unfortunately, many judges forget these truths, or simply don't care.
You should probably get an attorney to help you because your problem keeps repeating itself. Cases of mistaken identity are increasing. An attorney can help you file a police report in the right jurisdiction and can potentially help you get an identity hearing or appear with you before a court to help correct this situation. Attorneys are mouthpieces - they are helpful in speaking on your behalf and many courts give attorneys more deference than a driver who is representing oneself. My suggestion is that you get an attorney in your area for specific advice.