Maybe my cynicism is getting the best of me. Here is a neat article on the results of piles of data collected by mobile GPS maker Tom Tom. The company collected data on its customers and found that people, when faced with an open, uncrowded road, tend to drive at 70mph regardless of what the posted speed limits are. This ought to help you understand the difference between law (that which people customarily agree to and obey) versus legislation (what is says on paper).
In any case, the article presents the usual arguments for keeping the speed limits low and the usual arguments for raising speed limits. Virginia is one such state that has increased the speed limit on rural roads to 70mph. Initially I thought, “oh, that’s nice.” But then I looked at the picture the WSJ included with the article. Here it is:
So maybe what we’ll see is states raising speed limits and then lowering them, and then passing laws that speed limit signs ought to be neon mauve colorered, and then … just look at the bottom of the signs to see if they have the famous words, “this project proudly brought to you with funds from the American Recovery and Reinvestment Act of 2009.”