its something around 8-10% due to computer error from memory, so 88 in an 80, 66 in a 60 etc. think this is only with old model speed cameras.
I really really really really really hate it when people drive under the speed limit, i used to do pizza delivery and i was so keen to buy a megaphone to abuse people for driving slowly, still think about buying one actually. Fair enough if its raining or the road conditions are changed but not on the parkway, if you aren't comfortable doing 80/100 then hand in your license. That and asian drivers, (sorry to the token asian here ) they make the best food, they are the best with technology so its only fair they can't be gifted with everything