First thing you do when they ask you if you know why they stopped you is say..Yup, Going a little fast.
I have got out of quite a few that way.
Or...I knew you were waiting for me so I got here as fast as I could.
When the cop asks you “do you know how fast you were going”” exaggerate the speed to the high side. Tell him 80, 90 MPH. Then he comes back with “oh no you weren’t gong that fast!” See, now you have him on your side going in the right direction.