Yes, this is a speed trap, but primarily to the extent that an Interstate traveler (like me) or any visitor, doesn't necessarily know that Rapid City employs speed cameras. What a convenient placement: the only Interstate in town! I just checked Google Maps and sure enough, NB there's a standard b&w speed limit sign at least a half-mile earlier for 55 mph (or at least there was in 2019) after miles and miles of 65, with a smaller sign below that says Photo Enforced. Miss that little sign and the driver is a sitting and driving duck. The Cedar Rapids website says that the photos are for safety, but of course this part of the road is a big money maker. If the good people of Cedar Rapids REALLY wanted more safe driving they could put a large hard-to-miss billboard at the city limits on both NB and SB I-380 that says something like "Welcome to friendly Cedar Rapids. Please drive safely and note that our speed limits are photo enforced." Will likely make less money but hopefully gain even more compliance AND more friends.