[Jacks]

You might be surprised, if you're convincing you can sometimes get them to drop the demerits by paying the full fine. I had the points dropped on a ticket before, at the time I drove for a living and had a clean license. I explained to them how I didn't intend to speed and that I was willing to pay the whole fine but please don't ruin my insurance record (only works once I think). They usually care more about the money than anything else. Unless you are planning to plead innocent and fight the charges that is your best outcome.

Edit: Don't go into it aggressive claiming to be innocent, be apologetic and play on their mercy. You will also have to lie, if you admit you knew you were doing 70 in a 50 they aren't going to be very helpful. And really really don't mention the construction zone.