Unless the police are offering up a totally different version of the facts than your son's,
I see no reason for this summons. I agree that you..with or without an attorney assistance...should fight this one.
Faulty speedometer is not a defense to speeding, but it may help mitigate (reduce) the fine and points, as my colleague suggests. In any event, you admitted you were speeding (70 is still over the limit), so I do not see this as a case you want to go to trial with...I think getting the best possible plea deal should be your goal. Good Luck!
Even if the Judge did not, in fact, "waive your appeal" (i.e., have you waive your right to appeal), it is usually very difficult to withdraw a plea of guilty. The Judge probably did a full and thorough "plea allocution" in which he or she asked very specific questions about what you did that you are pleading to, and likely questioned you about the fact that you, by pleading guilty, understand that you are giving up all your rights to a trial, cross-examine witnesses, etc. The burden,...
You didn't indicate what felony you were convicted of; Depending on the nature of your case,
whether you avail yourself of the various programs offered by Corrections, whether the DA or victim (if any) files a statement with parole, and your behavior in prison..you may be released after serving only a portion (few months) of your sentence, and very likely not more than 2/3rds (or 8 months).
I agree with Mr. Langer. There is nothing criminal here, so "pressing charges" is not a solution.
There is a saying that no good deed goes unpunished; This certainly applies here: You did this guy a big favor and, simply put, you got screwed ...(pardon my language).
The only solution would be a civil action...small claims court would be the easiest way to go, as my colleague suggested. However, any judgment you get will likely be difficult, if not altogether impossible, to collect. Good luck!
I agree with Howard Schwartz; In addition, I would add that it is inappropriate for anyone (prospective employer, etc.) to inquire if you have been "arrested", as an arrest is not evidence of guilt....the appropriate question would be whether you have been "convicted of a crime" and as Mr. Schwartz has said, Disorderly Conduct is NOT a crime, but a mere violation (i.e., below a misdemeanor). Good luck!