Agree with above. If you try to blame anything on GPS the local town prosecutor and judge will just laugh or get more pissed off or just be silent and think how they can ********* you over more
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Each state has different customs for dealing with traffic matters and even each town has its local quirks driven by the personality of whomever is the prosecutor and judge.
In NJ usually all people pleading not guilty get called in one by one before the court into some side room where the prosecutor reviews your situation and offers you some deal. This is where I might ask for them to change it to obstructing traffic, which by the way they hardly ever do because its like a $75 fine or so and no points or record as far as I have ever seen.
What they offer you 99.99% of the time is to change it to unsafe driving zero points but that is a bigger money maker for the State, maybe about $485 after all the fees and fines. With the unsafe driving pleading you can only use it something like once every 5 years or so but you'd have to lookup the details of that, and it still shows on your driving record just zero points so insurance can still bug you for it.
The only times I had gotten a ticket switched to the obstructing traffic and walked out basically scot-free just about $75 poorer, one time I knew the prosecutor locally on a first name basis since i lived in the town and the other time I was working late, walked into court late, they where just doing the last case, I went over to the prosecutor and we huddled in the back room, he said he didn't think the judge would go for obstructing traffic but he would try it since they all wanted to go home,,the judge said ok and that was that. Kind of different luck both times.
Your other option is to ask for a trial and make them prove the sign was there. Since I don't think its there any more you could take a picture of "no sign". If you bring that in with you the prosecutor might then go for the obstructing since you might win if you fight it. Usually if you fight it you might have to come back a different day and they have to call the cop in so often they offer you the unsafe to save themselves the trouble and costs.
None of your 4 points you listed will get you any sympathy and would probably just get those people more infuriated and one last thing,,,don't always trust GPS. Sometimes my GPS tells me things like to go back a few miles go around some block and come back to where I am, LOL,,,just use your brains first, GPS second.