How To Beat A Speeding Ticket Avoiding, Contesting and Beating Speeding Tickets

Speeding ticket driving through Oregon, I live in California, can I keep off record?

I was driving from WA to CA and got a speeding ticket about halfway through oregon on 1-5. The cop said I was going 80 at a 60 area. The reason for me speeding was that I-5 kept switching from 65 to 60 mph. I must have mistakenly thought I was in a 65mph area. Also, I later noticed that the truck (not mine) speedometer is off by about 5mph... So while I thought I was going 75mph, I was actually going 80mph. So this is a combination of keeping up with traffic (I was going only a hair faster than traffic), loosing track of the speed limit, and my speedometer being off. Anyways. So I got a ticket, and I really can't afford a ticket, much less the insurance premium hike up (I am unemployed and very poor right now). The whole reason we even drove those god-awful 1100 miles was to save money. I am more concerned with the ticket going on my record, as this will affect my insurance rate. Any suggestions on how I can reduce or eliminate this ticket? Any advice much appreciated. Thanks. PS. I am otherwise a good driver.
Im not making excuses, Im just being as thorough as possible for those actually interested in offering advice.

And the speedometer being off took me by surprise... Its not my car, so I had no idea. I mean, when he gave me the ticket I was kind of pissed, cuz when he pointed the laser gun at me, I immediately looked down and my speedometer was mid 70s... I assumed he had rounded up, but later on we drove past one of those "your speed is" and noticed that our speedometer was off by about 5 mph...