Sandy Myhre (the first woman member of the NZ Motoring Writers Guild and the first woman member and first President of the NZ Motorsport Media Association) has written an article for Xtra on Hiding Cameras and Facts.
UK data has found that excessive speed was the major factor in only 12.5% of crashes and that 70% of the crashes caused by excessive speed had the vehicle travelling under the official speed limit.
This reinforces my point that one should focus on educating drivers to drive to the conditions. Often driving at the speed limit will be far too fast for the conditions. At other times it is safe to exceed it.
On the weekend I saw a car spin out of control just ahead of me on a road in Thorndon. They were driving at under 50 km/hr but it was a raining and a corner so it was too fast for the conditions.
I agree with Sandy that a more effective way to lower the road toll would be far tougher drive testing, including in my opinion having to resit the exam every ten years.