Re: Sigh.
Speed is not dangerous in itself - it is a difference in speed that causes problems. (Like falling is fine...until you stop)
Plus yes, being a self righteous *ick and doing significantly less that the limit may be legal but it is certainly not safer. Through your actions you are causing others to react in a way that they would not do otherwise.
If you feel you need to do 20mph in order to react to events in time - maybe you should let someone else drive?
(ooh, look a road sign Icon)