The term double jeopardy as it applies to criminal law. I believe it to be a constitutional issue.?

The Fifth Amendment of the Constitution says that no person shall be subject to the same offense twice. If you plead guilty and pay the fine, you can't be prosecuted again for that offense.

Criminal Records Search Database : http://www.infosearchdetective.com/

Our government have brought this in in UK law after the police messed up an investigation into a particularly horrible murder of a young black lad by a white gang.

I think it is wrong very wrong and against the whole spirit of our unwritten Constitution and indeed Habeus Corpus first signed by King John in the 13th century. Then you can not expect anything different from an incompetent government such as ours.

Yes they can, if the new charges are any different at all from the ticket itself. Example: You get a ticket for littering. But, during the same incident, your cigarette butt caused the destruction of public property. You pay the ticket for littering. You can still be charged with criminal negligence for the property destruction.

No.

I don't know anything about Pennsylvania specifically, but I am aware of no state that can or does do that.

I am not a lawyer, but I believe so-- the driver did not go to court the first time.

However, why would they do so? The driver has already paid the fine. If it's a matter of another charge, (for example if you were speeding, paid the fine, and then they decided to charge you with reckless driving), that is not double jeopardy.