If you get a traffic ticket, are you required to prove your innocense or is prosecution to prove your guilt?

I got a ticket and when in the court, I was offered by the prosecutor to accept another charge with higher fine but no points on my license. I said I did not ignore any stop sign, he told me it is a matter of my word against the police officer's word; and that the judge will go by the word of the police officer. Everyone knows that police officers are given ticketing targets and they issue tickets to meet their targets. Why would the udge not accept the accused word. Remember the accused is not a professional at making up tickets.