When I was an IP at the RAG, we had a stud (stellar officer, solid pilot, and all around good guy) who got busted going somewhere around 127 in a 65 on his motorcycle. He didn't say anything to the squadron about it.
In the PRCP (People's Republic of Cherry Point), PMO regularly collects blotter entries on servicemembers from surrounding police/sheriff departments and distributes them to the base commands.
When the MAG CO found out about it, he nearly had a stroke. The officer was immediately removed from training, given an adverse fitness report, and reassigned to MAG. They were even going to FFPB him for it. On what grounds? I don't know. It's the PRCP. They don't need a reason. Just a place.
The main reason that he was in trouble was for "lying by omission" to the command. He was eventually returned to training, but only after a great deal of redass. Things did not work out well for him in the long run.
This is probably an aberration based on the other stories posted here, but you never know. When I was a 1stLt I would have probably done the same thing (i.e. nothing). But that was before the information age and the zero defect mentality came along.
I would recommend that you:
1) Don't speed.
2) If you do, don't get caught.
3) If you get caught, tell your CoC as soon as reasonably possible starting at your immediate supervisor. Get advice from him on how to proceed.
YMMV.