I don’t know if the speed trap you mentioned was the same one I saw, but right at the town limits of Amidon coming from the east, there was an old patrol car parked, complete with a dummy officer. It was pretty obvious when I was there (Wed 6/18) that it was just a decoy, since the weeds had grown up around the car. But someone may have cut them down since.
I went through Amidon myself in August of 2003. I don’t remember the patrol car, maybe because I was fretting about running out of gas at the time — especially once I realized there was no place to buy gas in Amidon.