There is an unused (new) bridge going over hwy 44 east of Rapid City. There is one patrol car on this unused bridge taking speed measurements. Approximately .25 mile east from that, there are 3 to 4 patrol cars pulling over people that the patrol on the unused bridge measure as speeding over the posted limit.
The posted speed limit is 45 mph at that point, which is not an unrealistic limit due to merging roads (traffic) in the area. I don’t know if this qualifies in your definition of a "speed trap" and i did not get a ticket (as I rarely go over the posted limit)but, I feel as though my liberty had been stripped away.