Are there any which appear to flash with a blue light?
Do they still have Average Speed cameras in that area?
Could be anything these days - some HGVs are festooned with blue lights on their front. How do they get away with it?
I have often wondered about this. In a continuous road with several average speed cameras, do they detect a speeding vehicle by its registration plate and automatically "tot up the average speed across a range of cameras, or do they simply detect excess speed on one camera then check it at the next camera and send a NIP/FPN (or whatever) if the average speed is above the accepted limit?
http://www.speedcamerasuk.com/specs.htm