Not sure of the relevance of all this when the average speed scameras in our are are clearly set well above 60 mph in a 50 zone. Reality is that most people drive at the traffic flow speed except on the open road where overtakes might actually achieve something. In 30 limits and the like you trundle on at the same speed as everyone else confident that the authorities arent daft enough to set the scameras to catch everyone.
Maybe I am tempting providence but I dont watch the speedo so much as go with the flow and I havent been done for speeding since 1989.