You know what this country needs? A complex system of variable, ever-changing speed limit signs, so nobody can ever argue with the cops about whether they've been speeding. Done.

I do agree with this part:

...Crashes are not related as much to speed as to the range in speeds from the highest to the lowest. Studies show that, regardless of the average speed on the highway, the more a vehicle deviates from the average speed, the greater its chances of becoming involved in a crash.
But to me, that means setting speed limits that are more in keeping with the natural flow of traffic on a given stretch of highway. Sadly, politicians and lawmakers think the above means that they have to slow everyone down.