[magduf]

>The safest speed limit being one that the overwhelming majority of people would naturally follow were it not posted is basically considered fact in the civil engineering world. There is study upon study backing it up.

It's too bad the civil engineers working as traffic engineers absolutely refuse to actually follow the recommendations of these studies. Honestly, I can't think of a more intellectually dishonest profession than civil engineering (specifically, the traffic engineering subset of it; the guys who build buildings and bridges are OK).