Been driving now for about two decades and despite having lived in 5 different states in that time (and driving through most of the others), and despite the fact that I exceed the posted speed limit regularly, I have never gotten a single ticket.
And mind you, I've lived in some areas where the cops love them some tickets. Particularly Washington state, where their tax system necessitates them not only milking drivers any chance they get, but hitting them VERY hard when they do. I heard some horror stories out there from other guys in the Navy about some very sizable fines.
My secret? I am reasonable about it.
I go over the limit by a reasonable amount (4 or 5 mph usually) and it's very contextual. I pay attention to my surroundings, I make it my concern to be aware of the speed limit by looking for signs, and if it's daytime and I'm on the highway between towns (frequently am) I will go up to maybe about 15 over the limit in certain circumstances, if the rest of traffic is doing so, etc. I make sure I'm never the juiciest target for the cops, though. I always let some Massachusetts driver (I'm in Connecticut and they zoom through) be the fastest one out there on the road. They oblige.
At night, it's much easier to be the most tempting target for the cop because you may be the only car he sees for a while. So at night, I am more careful still. 4 or 5 mph over on those same highways, and not an iota over in the towns.
Your situation sounds like it may not have been entirely your own fault if it was a 5 lane and if the speed limit signs were poorly placed (if I read you right, the last sign you could've seen was a 50 and you hadn't yet reached the first one to say 40?) so I sympathize. If you go to court over it, I agree with what someone else said, be respectful and humble.
And whether you beat this ticket or not, use this as a learning experience and from now on, play it smarter and be more reasonable about how you speed. If you don't, you'll be paying a lot of tickets over the coming years. Particularly if your state needs revenue badly.