Here in the People's Republic of Maryland, we have both kinds of speed cameras, those mounted and those inside the damn Ford Windstars that they keep moving around. The neighboring Disney-North (DC) has fixed ones only. Don't want to get into the never-ending radar detector thread, but a detector will pick up the radar that these are run off of. If snapped, you get a nice sheet of paper with front and rear photos to show both you plate and face and instructions. Believe it or not, the system here is run in entirety (includes fee collection for profit) by a subsidiary of Lockheed Martin!!!
The ones on the poles will flash, I know that one for sure. Some neighbors have gotten awards from the van-mounted cameras and said that they never saw a flash. Both kinds here are set exactly 10 mph over the limit, but yours may be different. There was a Washington Post article a while back about how many of the things are broken, so you may be lucky from that aspect, too.
Either way, you'll know in a couple of weeks. The one nice thing about the cameras is that they are sent to the vehicle's registered owner, so you as an operator do not get points on your driver's license.
Bob