31-05-13, 06:28 PM
A bit tricky to tell without a diagram or google maps reference, but it sounds to me as if they may have been set up to catch traffic travelling in the other direction. You'd have needed to be a fair distance away in any case (i.e. well into the 50 mph zone if I'm understanding your description) before you appear to be moving at 48mph from their equipment's point of view. (It only measures speed in line with the camera... you could ride flat out in a big circle around one of their fancy laser measuring thingies and it would register 0mph).