When you appear in traffic court, what you say when speaking to the judge can make a difference in the fine you receive and, sometimes, between being convicted or acquitted
Going to Court
Most traffic ticket fines can be paid by mail without a court appearance. However, you must plead guilty and pay the maximum fine. You should appear in court if you feel there are mitigating circumstances or if an explanation of your conduct is in order, even if you intend to plead guilty. You must appear if you intend to plead not guilty.
General Conduct in Court
You likely will have to wait an hour or more before your case is called. While waiting in the courtroom, do not make any noise, talk to others or in any way disturb the court proceedings. When your case is called, respond immediately by saying "Here" and walking up to the rail. Address the judge as "your honor," and be respectful. Do not interrupt the judge or raise your voice.
What to Say in Court
If you believe you did not commit the offense with which you are charged, clearly and concisely explain why. The judge will only consider a factual argument, not something like "that cop was out to get me" or "there are too many speeding tickets given on that street."
If you intend to plead guilty but believe that there are mitigating circumstances, this is the time to assert that. For example, you might tell the judge that the stop sign was concealed by a tree, that traffic was heavy and you had difficulty watching your speed or that you thought you signaled for a lane change in adequate time. Make your argument firmly, but respectfully.
A third option is to plead not guilty and ask for a trial. The downside of this is that you will have to appear in court again, but the case may be dismissed if the arresting officer does not appear. Do not expect to be acquitted unless you can conclusively demonstrate that you did not commit the offense with which you have been charged. Unlike most criminal trials, the burden of proof tends to fall heavily on the defendant and the court is likely to take the word of the arresting officer over yours.
What May Happen
If you plead guilty, your fine will usually be less than it would have been if you had simply mailed it in. The judge has some discretion to reduce your fine, particularly if you offer an explanation. The judge, for example, may take into consideration your driving record. The simple act of showing up in court is considered to an act of civic duty and for that reason alone a court might impose a lower fine.
It is possible that your explanation may induce the judge to dismiss the case. This can occur when your explanation is logical and firm, particularly if you feel strongly about it and can show that. You may have violated a traffic law, but you should not have been charged in this case. Of course, if you simply believe that you did not do it, you should plead not guilty and ask for a trial.
Since you are dealing with a human (the judge), many outcomes are possible, even in nearly identical situations. Use the time while you are waiting your turn in court to observe the judge, see what kind of behavior and language she responds to, both positively and negatively, and try to gauge her mood and demeanor. Prepare yourself mentally as you would for an important interview.