The fact that people are doing something doesn't make it okay. Away from urban areas I have no problem with a 65 or 70 mph but not inside the city. I'm sure that the traffic engineers know more than I do but in traffic that heavy and the major tailgating in Charlotte 55 seems safe to me and should be enforced. The chief problem as I see it is that way too many local folks think they are above the law. Just sit on any urban or suburban street corner and watch; if you are honest with yourself you'll know what I mean.