For the purpose of challenging a speeding ticket, how often do the tuning forks need to be certified with the State Superintendent of Weights and Measures to be considered valid in NJ?
There is old case law, I thinK it is State v. Kalafat (?) that says every year. This has worked in some courts before. Not in others. However there also is case law that allows a cop to eyeball at 2 point speeding violation.
I strongly urge you to HIRE A LAWYER (caps intentional).
My guess is that you have about as much business practicing law as I do piloting a space shuttle... meaning none. Please understand that this is not personal to you. It is a simple truism in the legal profession. It is very easy to screw up a case when one does not understand the complexities of the rules of evidence and the rules of procedure; and you are very likely to screw up your case if you serve as your own lawyer (ergo Abe Lincoln's famous quote... "He who represents himself has a fool for a client.").
That said, in my opinion, the best defense for any traffic citation anywhere is to hire a local traffic ticket lawyer. I can't speak to the ______ area per se but in Miami, Fl where I have been a practicing criminal defense lawyer for nearly a quarter of a century, there are many skilled and experienced traffic lawyers who know the law, the procedure, the Judge and probably the cop. In short you will almost certainly get both competent representation and a better result for a relatively small fee / investment.
That said, I hope that I have been helpful in answering your question.
You need an attorney. IF you want to do your own research, you will need the make and model of the machine used, the user's manual for the machine, and also the log from the service records.