This, I believe, would be basically the right approach. Talk to the prosecutor first when you get to court, and say this. Instead of the last sentence, though, which might seem a little presumptuous, I’d substitute “I respectfully ask that the case be dismissed, and I’ll be sure not to do this again.” If the prosecutor won’t dismiss, he might reduce the charge to a lesser offense (if one is available). If you don’t want to insist on a trial and the prosecutor won’t reduce the charge, make essentially the same statement to the judge or magistrate when you appear before her, and the fine might be suspended. No guarantees, however. Good luck.
In which case, don’t even mention the other law. In fact, if the judge brings it up (which I doubt, since he probably doesn’t have them all memorized) don’t even acknowledge it. (Well son, there is this other law that states that you can’t do that…I’m sorry your honor, I had no idea it was against the law).
ETA I mentioned before about calling the police station and finding out what the various fines were. Two things to add to that. First off, don’t mention that you got the ticket, just ask what the different fines are. This way if the one you received is the same as what they tell you on the phone, you know that everyone is on the same page so to speak. Also, ask how much a littering fine is. It’s most likely more, but if happens to be less, you might be able to ask the judge to just change it to littering.
And whatever you do, don’t play the “But the OTHER cops didn’t give me a ticket” card.
It doesn’t matter, legally, and trust me, they will all have heard that song way too many times.
Unless before you started you specifically asked the other cops if it was OK, and they said yes, absolutely, and you have in recorded or in writing somehow.
With a $114 ticket, I’m guessing you’re not plea-bargaining for a lesser offense with a prosecutor, so much as directly asking a judge/magistrate to drop it.
Your chances of getting out of it depend on how much effort the court is putting into these violations right now; if the cop just felt like writing a sloppy ticket on a non-focus issue because he was grouchy that day, you might well get it tossed due to his mistake. If there have been a lot of complaints and the city is under pressure form the school/town/whoever to cut down on grafitti/signs, they’ll find a way to make it stick no matter what you say. Probably something along the lines of asking the officer to make a correction to the ticket on the spot and then proceeding as usual (ie you lose).
Every spring in my town the city sends word through the news that they will be fining people who put up illegal signs on city property (the type like “lawn aerating - call xxx-xxxx” taped to a stop sign). Then they go out for a few weeks writing tickets, and then issue another news story telling how many thousand $ worth of fines they handed out. When the campain is over they promptly turn a blind eye on the same signs until next spring.
As stated already, the law isn’t enforced in a robotic manner exactly as it’s written; depending on the circumstances and outside pressures the courts might let a gang hitman walk while throwing the book at a jay-walker.