[tjts1]

Speed limits on the highway are inherently dangerous and serve no purpose other than a source of money for local government. A portion of the population is going to break the law whether you set the limit at 55 or 70. The worst part about it is the complete lack of lane discipline in America. The concept of "slower traffic keep right" is completely lost on some people. A lower speed limit would encourage more slow drivers to use the left lane presenting a road block to everybody else. Speed alone isn't inherently dangerous. Its the difference in speed that will kill you. The prime example of this is the carpool lane at rush hour. 3 lanes sit in stop and go traffic while the lane immediately to their left can moving at 60mph. Try merging into the car pool with that kind of speed differential.

I like to look at the Germans as nice example. Anyone that has driven in Germany knows that there are speed limits on the Autobahn. But the speed limits change based on traffic congestion, time of day and weather. This can range from 100kph in on a crowded stretch through Munich to unlimited on the open road. I don't think any single speed limit right for all places all the time.