Are you serious?... You think they HAVE to be in plain sight so you can SLOW down?.
No, They can be up in the freaking tree's with a radar gun. Thats what speed traps are. The only reason they are often in plain sight is because it's hard to hide a huge crown vic on the side of the freeway.
You got caught, there's nothing you can do but contest the ticket and hope he doesn't show up. You have no case if he shows up.
Wrong....there's plenty of ways to get out of tickets.
Here's one way i got out of my 95mph speeding ticket at court. Bear with this long story, it may be useful for your situation.
Scenario:
I was heading towards butt f*ck egypt to do a side job in Palm Springs, CA. It was already 9pm and i was late 2 hrs as it was and it takes 1hr to get there from my apartment so i decided to bring the speed up to compensate for lost time. Im doin about 105mph on a 70. Cop sees me on the side of the road and runs after me(i saw him in the middle of finishing a ticket and he runs to his cop car and hauls ass to catch up to me). Obviously i saw him do this so i slowed down immediately to 65mph and he finally catches up and we both pull over after his lights turn on.
He asks me how fast i think i was goin and I say "i dunno, im pretty sure i was doing about 65mph". He laughed and then started throwin a fit out of no where. I calmly said "well if you feel different about my opinion then write me the ticket and we'll settle this at court". He writes me the ticket and we go about our ways.
Court Day:
So i show up to court and wait HOURS to see the judge after the second time to court (the first time you show up to court is to plead not guilty). I give my short speach on how my ticket was inaccurate and the judge says "what do you mean inaccurate?". I say "well, first off, the officer didnt put his serial number of the radar number on my ticket". So i look at the officer and ask him "did you use a radar gun to clock the speed i acheived here on this ticket? And if so, when was it calbrated last, because if i check this unknown serial numbered radar gun, im sure its calibrated inaccurate". The officer replies, "i used a lidar gun". So i shake my head and say, "ok".
The previous day before this day i got a ticket for a no front license plate (stick with me, its gonna make sense why i made this quick statement). So i asked the officer again "so if you used a lidar gun, how does it operate? How does a lidar gun work??" The officer quickly explains " well, it uses a beam of red light that is supposed to be pointed to the front license plate of the vehicle and it returns a light signal back which tells the gun how fast you were going". So i said, "so how is it possible that you determined i was going approx. 95mph when i had a ticket the previous day for having no front license plate??".
The judge dismissed the case and chewed out the officer. The judge actually told him he ought to find a new career with the sloppyness of this case and the lack of proper judgement.