It’s been my experience that the judge will find for the prosecution, regardless. One of the questions he’ll usually ask is, “Are you trying to tell us that the officer was lying?” How can you possibly answer that one?
With a jury, though, you can introduce reasonable doubt. Also, if a jury finds you guilty, it gets to set the fine. That fine can be raised or lowered, depending upon the case you present. Furthermore, it can lower the charge – if you say convincingly, for example, that when you spotted the cop, your speedometer read 41, the jury can lower the charge to 41 in a 35 zone. Or, they can completely dismiss the charge as false.
However, if a jury thinks that you’re wasting their time, they’ll find you guilty regardless. It’s best to at least act like the wronged party.
If you choose a jury, make sure that you poll them first. Ask if any potential juror currently works (or formerly worked) for law enforcement. Also ask if any of them think that the police are always right. It might help to ask if any of them think that radar is infallible. You can ask for a show of hands: take notes on who answers what. It might help to write down your questions first. You’ll be allowed to present a list to the judge of who you’d like to serve, and who you’d prefer to strike. So will the prosecutor: the judge will then select a jury from both lists.
When you go before a jury, expect the prosecution to object to some of the issues you raise. Be prepared to counter the objections with the argument that this pertains to the case, and say why. When you take the stand, be very careful during the cross-examination. Remember, the prosecutor isn’t sworn to oath, and will lie about what you said to further his case. Also, pay attention to the instructions to the jury about setting a fine: if they’re worded as a presumption of guilt, object on those grounds.
And yes, it’s probably best to have a lawyer experienced with traffic court on your side. You alone might get swamped against the forces of government, but a lawyer will know many of the tricks that you otherwise wouldn’t think of.